L046 Biotype Small fish ideas

[shortykilogyrl]

I am setting up a Rio Xingu biotype for 3 zebra plecos and I'm looking for ideas as well as researching for mid to top dwelling fish that stay under 3". Does anyone have any ideas?? I would greatly appreciate it!

[TwoTankAmin]

If you want to recreate the actual conditions where zebras live, the answer would be none. Most would be washed downstream. And then there is the depth at which zebras live. No light to speak of down there, so no live plants nor algae. And finally there is the temperature, which is too warm for many fish.

That said. If you want a tank with zebras which you may rarely see, perhaps rummy nose tetras would work. They can take it warm. Maybe there are some others. Check on some rasboras as well to see if any of them work in zebra temps. I would leave the zebras as the lone bottom dwellers.

I am assuming since the 3 zebras will cost you more than everything else that goes in the tank combined that you are setting the parameters to be best for them.

In terms of doing a zebra set-up, there is a two part article on this site at Shane's World-
http://www.planetcatfish.com/shanesworl ... cle_id=387
http://www.planetcatfish.com/shanesworl ... cle_id=400

[shortykilogyrl]

That's what I have been learning recently. I 100% plan on leaving the zebras as the sole substrate fish. I am only looking to add fish to the mid and top level of the tank. And nothing too boisterous, something calm and peaceful. I do plan on adding a spray bar off a canister filter to create flow in the tank for the zebras. I use RO/DI water and my water comes out with Equilibrium and pH neutral added almost perfect for the zebras It's nice being able to adjust as I see fit between each tank as I wish.

Thank you for the ideas for the rasboras or rummy noses. I have read lemon tetra as well work but I am going to research that further

Thank you as well for the links I will check them out!

[racoll]

If you want to recreate the actual conditions where zebras live, the answer would be none. Most would be washed downstream. And then there is the depth at which zebras live. No light to speak of down there, so no live plants nor algae.

I am not entirely sure about some of these statements.

Regarding depth, I have seen wild photos of H. zebra in what is clearly sunlit water. I think maybe they have simply been over-exploited in the shallow areas, but I would be happy to be corrected here.

I have never collected H. zebra myself, but the other species of

Hypancistrus

I have collected (6 species), none have been from the raging torrents people always assume them to come from. Most have been from completely stationary water, and not deep at all (< 1 m). They are not like a

Pseudancistrus

.

There are many, many fishes that coexist with Hypancistrus, including some you would not expect, such as discus and angelfish. Where the current is a bit stronger, almost ubiquitously you will find lots of anostomids. However, it is rare to find these in the trade.

The majority of the tetras you do find in the trade are sourced from small forest creeks with much cooler water. The tetras you'll find in the bigger rivers tend not to be so colourful, and so are not caught for the trade.

In short, you are very unlikely to be able to find an exact biotope match, but there are species that will do okay. Lemon tetras I seem to remember catching in very warm water, so these might be a good option, but do of course break the biotope ...

[bekateen]

What about golden tetras? I seem to recall that they do well in warm water. Is that so?

[shortykilogyrl]

If you want to recreate the actual conditions where zebras live, the answer would be none. Most would be washed downstream. And then there is the depth at which zebras live. No light to speak of down there, so no live plants nor algae.

I am not entirely sure about some of these statements.

Regarding depth, I have seen wild photos of H. zebra in what is clearly sunlit water. I think maybe they have simply been over-exploited in the shallow areas, but I would be happy to be corrected here.

I have never collected H. zebra myself, but the other species of

Hypancistrus

I have collected (6 species), none have been from the raging torrents people always assume them to come from. Most have been from completely stationary water, and not deep at all (< 1 m). They are not like a

Pseudancistrus

.

There are many, many fishes that coexist with Hypancistrus, including some you would not expect, such as discus and angelfish. Where the current is a bit stronger, almost ubiquitously you will find lots of anostomids. However, it is rare to find these in the trade.

The majority of the tetras you do find in the trade are sourced from small forest creeks with much cooler water. The tetras you'll find in the bigger rivers tend not to be so colourful, and so are not caught for the trade.

In short, you are very unlikely to be able to find an exact biotope match, but there are species that will do okay. Lemon tetras I seem to remember catching in very warm water, so these might be a good option, but do of course break the biotope ...

I have seen many posts of zebra and lemon tetra together. That has definitely been an option.

[Jools]

My dither of choice is the

Harlequin Rasbora

.

Jools

[TwoTankAmin]

I am basing what I posted on a presentation I attended a couple of years ago by Hans. He described his experience of diving with locals who were collecting zebras some 10+ years earlier. He wanted to learn how it was done and see where they were found etc. I recounted the conditions as he described them. As to how accurate the descriptions were I cannot say since I have never even been to Brazil. But I tend to to accept this description for other reasons:

1. The over abundance of wild caught males in relation to females supports an inability to find females with ease. The method of capture was described as being one of feeling for fish that are captured not seeing what was being caught and the use of a net or other device.
2. The fact that zebras are collected seasonally because during the rainy season the water is simply too deep and fast flowing to make it possible. If zebras were easily found in shallower waters, there should be no problem with year round collecting.
3. Part of the presentation recounted the other divers discussing where other collectors, sometimes even relatives of those he was with, had been drowned during attempts at collecting. This is not a huge risk in shallower waters. Why would collectors risk death when there was no reason for this?
4. Finally, the reputation of the speaker himself would suggest to me his report was valid.

I would also add a bit of anecdotal evidence. I have raised pleco fry from about 8 different pleco species- all smaller and mostly Hypancistrus. Like many folks I had 100s of bn fry over the years. For the most part I have regularly siphoned fry to get them out of tanks. The first time I tried this with zebras I learned that the fry go in, but they don't come out. Unlike other fry which just fly through the hose into the bucket, almost every zebra fry was able to suck onto the inside of the hose and hang on in the flow there. I learned quickly not to use this method. So now I net them and often have to use an icing spatula to pry them off the glass into he net. For tiny fish they have one heck of stick-to-itivness. They seem especially suited to surviving in strong current.

If all the zebras in shallow waters had been over collected, it would have had to have happened by the very early 2000s since the trip reported occurred then. But this does not jibe with my personal experience in finding wild caught zebras over the years. It was harder to acquire wild caught fish when I got my first ones in 2003 than it was for me to find them in the past few years. This does not support the overfishing the shallows for them forcing collectors to move deeper idea.

I did find one study which might help clarify this issue somewhat, but it is in Portuguese. I could not plug the document into Google translate because it was too large. But I know there is depth data included. Here is the English version of the Abstract that is included:

Ecologia e etnoecologia de Hypancistrus zebra (Siluriformes: Loricariidae) no rio Xingu, Amazônia brasileira
Alany Pedrosa Gonçalves
Belém-PA
2011

The distribution of H. zebra is restricted to a small stretch of the Xingu River, between Gorgulho da Rita and Itaubinha, and does not occur evenly, it depends on the presence of boulders. A total of 283 individuals of H. zebra were visualized in the rocky outcrops of the study area, of which 232 were captured. The lowest average abundance was Gorgulho da Rita, as opposed to the site Jericoá with the greatest abundance. Between periods, there was a greater abundance in dry river and lowest value
for the period of filling. Environmental factors had no significant influence on the abundance of H. zebra. H. zebra is a generalist species, feeding mainly of periphytic algae, debris, plant debris and sponges, while nematodes and millipedes were considered occasional items. Diet composition and abundance of H. zebra showed no significant differences for collection sites, periods of the year and ontogeny. Considering the composition and abundance of the diet, H. zebra can be considered an iliophagousomnivorous, and ability to adapt changes in food availability in the construction of the Hidroeletric Belo Monte. Ornamental trade fishermen demonstrate expert knowledge concerning the distribution and abundance, habitat, feeding, predation and reproduction of the H. zebra, which can be used to optimize work and to facilitate future management
measures. The construction of the Hydroeltric Belo Monte Hydroelectric is a threat to the survival of H. zebra and future studies and monitoring of the species are needed, either as mitigation of impacts, either as to captive breeding as an alternative income coastal communities who depend on fishing on the Xingu river ornamental.

from http://www.ufpa.br/ppgeap/images/storie ... 202011.pdf

They present depth and flow data for the collection points.

And here is page 151 from the Catfish Atlas Vol.1 by Ingo and Hans:

from http://books.google.com/books?hl=en&lr= ... er&f=false

I may be off the mark in all this and I am happy to be corrected as I love knowing as much as I can learn about these fish. I would love to hear from people who have been there and have first hand experience.

[racoll]

Thanks for digging up that link.

As I suspected, the majority of H. zebra are caught from shallow water of less than 5 m (see Figure 4-5). It seems that due to the extremely high value of these fishes, diving to extreme depths is worth the risks for the small number of extra ones. They are certainly overfished, and I guess this is more pronounced in the shallower areas.

Also makes sense that there are more in the shallow water due to the greater abundance of the algal biofilms on which they feed.

[7Pete]

Teleocichla-species are small and interesting fishes which I would consider with H. zebra. They live in same kind of rapids as hypancistrus and most of other plecos. Teleocichla sp. Xingu is suitable for your biotope aquarium.

[TwoTankAmin]

racoll- you made me put Google translate to the test and I cannot say what I found agrees with what you wrote above.

First, this is what was stated regarding Figura 4-5:

The occurrence of H. zebra at depths ranging from zero to fifty meters, with 97% of respondents stating fishermen's preference sort by shallows. There was a predominance of occurrence in places up to 10 meters, with no record of individuals in places over 15 meters deep (Figure 4-5).

The problem is none of the bars is black and then they have reports for fish collected at depths greater than 20 meters. So I have a problem with making sense of this. It is likely translation issues I would hope. I also do not see how the % information makes sense either. pasted the figure here. When I post if becomes a cory picture, but if i click on it, the figure comes up on another page.)

Here is the translation of the Figure 4-5 caption:

Figure 4-5: H. zebra occurrence depth of the Big Bend of the Xingu River. white bars represent frequency fishermen answers respondents in 2006 (32), bars rachuradas represent the fishermen in 2010 (40) and black bars represent percentage of occurrence of specimens by depth class

I have found references which say the average depth was 5 meters +/- 2m. I look at Figure 2-3 which breaks down the depths by collection location and they are not 2 meters almost anywhere. here is what Google translate gave me for the paragraph above Figure 2-3:

The average depth of the collection sites was 5 ± 2 m, with a minimum of 2 m Weevil Rita, in the dry season, and a maximum of 13 m in Belo Monte, from full. The sites Farm Island and Belo Monte showed the greatest depths medium, Rita of Weevil intermediate value and Jericoá lower value

Doing the math the shallowest depth for collection anywhere at anytime of year would appear to be 3 meters which is almost 10 feet deep. 5 meters is over 16 feet and 13 m is over 40 feet. What is even more interesting in Figure 2-4 is the water velocities listed. the site with the shallowest depths is not the one with the lowest flow rates. Figure 2-5 indicates that the most fish were found at the greater depths. And Figure 2-4 which looks at the information on a seasonal (river level) basis would seem to indicate that the slowest water was not found at the shallower collection locations.

In the general information on page 34 it states this:

Depth (m): the average depth was measured at a distance of 20 meters with an echo sounder (SX HUMMNINBIRD 150) which calculates the distance through time between the emission of a sound pulse and the reception of the same signal after
be reflected by the river bed background. In addition, with the aid of a weight 25 kg tied to a rope and to measure the depth of the site where the vessel used for Fishing was anchored. The average of these two values was used as the depth of the spot.

That 20 meter average works out to about 65 feet deep.

The one last piece of information I have on this subject relative to over collecting is on another site in a sub-forum which is called "Ask Heiko." In early 2010 I got the following answer to a question I had posted:

Q. I would like to know what sort of population levels you observed in 1975 when you first came across the zebras. And then I am curious if you have been back in the past few years and if so how the populations today compare with what you observed in the 70s.
A. Hi,
in 1975 there was no way to observe the entire population in the region, time was to short. But there were many. To my later research, after going back many times, there was no reduction in its population (with other words it was not possible to see any decline whatsoever). But yes, there was a time when the former gold-diggers were heavy after those to collect them in one or two spots by the thousends. Which could have had a effect on it, but there was never ever any proof that this really happened.......
In the meanwhile the smuggeling of L-46 (Hyancistrus zebra) across to Colombia is in full swing, simply because everything what is prohibited on this planet by man, is deemed for extinction. Every animal or plant "protected" will be history, because prices go sky high (Colombians are paying between 80 to 100 US$ Dollare per L-46 and selling for $ 150 to Japan and the rest of the world - daily... I just saw it in December 2009 in Leticia with my own eyes...).

from http://www.plecoworld.org/modules.php?n ... opic&t=449

So I am still at the point where the evidence I see states the fish live "deep" most of the time and tend to be caught there. At least according to Heiko the species was not in danger from over collecting in general although it may have suffered in one location. But let us assume for a minute that during the period fishermen overcollected from the shallowest possible collection points. This might reduce the population levels at such a site. However, if the fish is normally spending much time living at those depths, they should be returning to them in some numbers even when the location has been over collected.

And finally, what about the statement by Ingo and Hans I quoted. I presume if one accepts what you are saying, then we also must assume that they are wrong in what they wrote regarding collection depths. This book was published in Nov. 2005 and must have been based on their experiences that go back some time since writing and publishing this work must have taken some time.

At any rate, I do not mean to sound like I am spoiling for a fight. I merely wish to get to the bottom of this so not only will I, but so will other people who read here, have a reasonable picture of where and how zebras live. So far I am still of the belief that the bulk of zebras appear to spend most of their time at depth and many are also captured there.

The other thing I wonder about is there are a few members on this site who are actually down in Brazil and doing research on the Xingu or who have visited on several occasions. It sure would be great if any of them could contribute to this discussion. Nothing beats first hand knowledge.

This all is about to become moot due to the dam. It will do one of two things. Either it will wipe out zebras entirely or else it will mean they live at dry season depths all year long. The Volta Grande (Big Bend) is about to get a heck of a lot shallower and lower flow. And it would not surprise me if the average temperature also rises as depth usually makes things cooler.

[racoll]

As you noticed, Figure 4-5 is not very clear at all, and the bar colours are mislabelled. It is not a translation issue. What you need to look at is the stippled bars, which report the proportion of H. zebra caught at each depth for both years, and add up to 100%. About 65% of the fish were caught from 0-5 m, about 30% from 5-10m, and about 5% from 10-15 m, and none were caught in water deeper than 15 m. The text states "97% dos pescadores entrevistados afirmando a preferência da espécie por locais rasos.", meaning "97% of the interviewed fishermen affirmed that the preference of the species was for shallow areas".

Figure 2-3 provides general information for the topography of the entire river section at the locations selected as fishing spots, but not the exact depths that the fishes were collected at on individual diving trips.

And finally, what about the statement by Ingo and Hans I quoted. I presume if one accepts what you are saying, then we also must assume that they are wrong in what they wrote regarding collection depths.

Their statements are not in strong disagreement with the data. I am sure H. zebra does occur in 20 m of water, it's just that it's less common. And bear in mind that without any equipment to measure the depth, you are trusting the fishermen to report accurately, and also not exaggerate.

And then there is the depth at which zebras live. No light to speak of down there, so no live plants nor algae.

I think this deep water vs. shallow water is a semantic issue. After all, as you say, even 5 m is still pretty deep. Really, what I was trying to disprove, was this initial statement you made. The data show what i suspected to be true, that most H. zebra live in areas with plenty of light, and plenty of algae for them to eat. They are simply not restricted to "the abyss" as most people seem to believe.

[cjp155]

Very interesting discussion on L046 habitat. I wish that someone could share video of L046 in their natural habitat for everyone to see for themselves what it looks like...

[racoll]

Jools added an aerial video of the habitat just the other day. Go to

Hypancistrus zebra

, and it's the last one in the long column of photos.

You may also be interested in joining the iXingu Project Facebook page. It is run by the scientists currently surveying the river, and they have posted probably thousands of photos of the Xingu and its habitats. There is even a current discussion of which biotope correct midwater fishes can be added to a zebra tank.

[TwoTankAmin]

Not even my desire to learn more about zebras will induce me to join FaceBook. If somebody wants to post the essence of what is there, it would be nice. But I understand there is no requirement to do so since it is my choice not to be on FB.

[racoll]

Not even my desire to learn more about zebras will induce me to join FaceBook. If somebody wants to post the essence of what is there, it would be nice. But I understand there is no requirement to do so since it is my choice not to be on FB.

Indeed. Indeed. It's a real shame that so much good information is locked away and then lost forever in this way. I do get sad when I see really interesting threads on Facebook, and think that in a couple of weeks it will be pretty much inaccessible. Here on the forum anyone can still search for and read forum posts from 10 years ago.

Unfortunately though, this is a common problem everywhere, as the internet becomes walled and "appified", and users are locked into agreements with corporations. It's certainly not in the spirit of the "good old" internet days when PC first started

[TwoTankAmin]

I agree. Good knowledge belongs where it will last and where it is freely available.

[Kasper]

Very interesting reading.

Sounds like algae could be a bigger part of their diet than what I expected or maybe something living on/feeding on the algae?

[shortykilogyrl]

Jools added an aerial video of the habitat just the other day. Go to

Hypancistrus zebra

, and it's the last one in the long column of photos.

You may also be interested in joining the iXingu Project Facebook page. It is run by the scientists currently surveying the river, and they have posted probably thousands of photos of the Xingu and its habitats. There is even a current discussion of which biotope correct midwater fishes can be added to a zebra tank.

that is more than likely me on there that asked that question and started the discussion lol

[shortykilogyrl]

I will try to copy and post what has been said in the iXingu project page:

Ashley Cardinal
25 February at 17:28
Thank you for the add!
I am in the process of researching for a Rio Xingu biotype tank and would love advice.
I am looking for middle to top dwelling fish that will stay under 2.5" and from the same locations (middle and lower Xingu) as Hypancistrus zebra (L046, true zebra pleco).
If anyone has any suggestions for me to further research that would be great, thanks!
I look forward to learning through this project!
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André Ribeiro Martins likes this.

Mark Sabaj Pérez
I do not keep live fish (only dead ones in jars), but pencil fish are nice top dwellers and species such as Nannostomus unifasciatus and N. eques are common to blackish tributaries to the lower Xingu. In Volta Grande...Brycon aff. pesu is an extremely common midwater fish. also common are various Moenkhausia (M. mikia, M. heikoi, M. collettii, M. cotinho, M. oligolepis, M. xinguensis). cheers!
26 February at 11:07 · Unlike · 1

Ashley Cardinal
Thank you so much! I went through 17 pages of a report and pulled out some to look at and narrowed that list down by what I liked and then by size as to what will fit the tank I have and then I'm going by pH, GH, KH, temp and habitat after that
26 February at 11:23 · Like

Ashley Cardinal
I'm also welcome to other suggestions. I'm researching these ones tonight
26 February at 23:31 · Like

Oliver Lucanus
given the availability, i would select Moenkhausia collettii not much else would be available. Perhaps you could find some other Moenkhausias. While zebra plecos don't live in the strongest flow, the flow you have will not be suited for Nannostomus species. I would get M.collettii or even M.sanctae-filomenae and maybe Inpaichthys kerri (not from Xingu but hardy and similar to Xingu species in appearance) or something like that. A common fish is also Chalcheus, but they would eat baby zebra plecos given a chance.
27 February at 08:03 · Like

Ashley Cardinal
I definitely would know want babies to get eaten. I saw Rivulus sp. are from the same area. However, I can't find anything to pin point which species. Having them would be great. I was hoping for something with brighter colors in it for the mid to top levels since the substrate will be neutral colors.
27 February at 08:12 · Like

Oliver Lucanus
the same area is relative: you can even find angelfish in the "area", but you would never see a Rivulus or an Angelfish in the same habitat as the zebra pleco. So it is not accurate to think they can go together. I think you would be better off to select fishes similar to those that occur in the same habitat, not the same area. Rivulus like standing pools with leaf litter and plants and very shallow water, in an aquarium with water flow, rocks and no surface cover they would not do well, or at least it would be totally unnatural.
27 February at 08:14 · Like

Ashley Cardinal
This project is proving to be difficult because I want to keep it as correct as possible. Finding good information that I can research from and a fish that is available is proving difficult
27 February at 08:17 · Like

Ashley Cardinal
So far Hyphessobrycon pulchripinnis seems to be popular in Rio Xingu biotypes which would be alright. Inpaichthys kerri are nice looking and would work, but shys away for the correct biotype too. So frustrating! lol
27 February at 08:23 · Like

Oliver Lucanus
the nature of the zebra habitat with big boulders in a large river simply means you have few small fishes that are not cryptic. They can not survive in that habitat. The Brycon Mark mentioned (i have it here) is fantastic, but certainly would eat baby zebras, as would Chalcheus macrolepidiotus. I think you are really limited to just the Moenkhausias, none of which are available with the exception of M.collettii which is one of the fishes found everywhere. You can usually find them mixed into rummy nose or cardinal tetra shipments from Colombia. You could also add some of the nondescript Hyphessobrycon-like tetras you see mixed into other tetras, they also exist in Xingu. This is a pic from the Xingu. One more fish you could add, and also find easily (albeit not from XIngu) is Characidium spp. They would not be in the open water, but perfectly fine with the current and rocky habitat. H.pulchripinnis is in the Xingu, but not in the zebra pleco habitat, it is not a fast water main river fish, it would fit better with the Rivulus in a planted tank.

27 February at 08:27 · Edited · Unlike · 1

Ashley Cardinal
I would LOVE to stick a school of neon's or cardinals in there and call it good but I have never done a biotype set up and thought if I'm going to put the money forth for L046 I might as well try and do it right lol
27 February at 08:28 · Like

[TwoTankAmin]

I apologize in advance for being so long winded.

Their statements are not in strong disagreement with the data. I am sure H. zebra does occur in 20 m of water, it's just that it's less common. And bear in mind that without any equipment to measure the depth, you are trusting the fishermen to report accurately, and also not exaggerate.

As for the depth reading, the authors state how that was measured at the various collection points reported. Here is the translation from Google re that:

Depth (m): the average depth was measured at a distance of 20 meters with an echo sounder (SX HUMMNINBIRD 150) which calculates the distance through time between the emission of a sound pulse and the reception of the same signal after
be reflected by the river bed background. In addition, with the aid of a weight 25 kg tied to a rope and to measure the depth of the site where the vessel used for Fishing was anchored. The average of these two values was used as the depth of the spot.

Average implies there must be numbers both deeper and shallower than 20m to produce that average. Oversimplified-if one location is 5 meters deep another would have to be 35 meters deep to average 20. How much deeper than 20 m was the river and how deep did the divers actually go? Unless they explored the depths at the height of the rainy season, how can we assume what was there?

Much of the information in that study was collected from fishermen. Not food fishermen but ornamental collectors of fish. If you look at the time frame involved it was pretty much during the peak of the zebra frenzy where prices were through the roof. Even the study indicates that fish were being sold for about $100 by the illegal exporters. In that period I was offered over $8,000 for my breeding group. I was down two fish from my original group of 13 which cost me nothing near that amount. I was not smart enough to take the offer.

What I wonder about is why the majority of the fishermen would be honest in revealing their "trade secrets". Specific locations are what makes them their money. Given the value of these fish at that time, if they were fairly easy to find and capture, I think the river would have been pretty busy with folks looking to collect them. So the collectors may have selected spots where they knew there were zebras but which may not have been the best places to find larger numbers, or it might have been the best location. We have no way of knowing.

As I said above this confuses me. If the average depth was 20 meters, what exactly does this imply in terms of where the zebras are? The only thing we can say for sure is that being sucker mouth catfish, they live on the bottom whether that is 3 or 20 meters or more deep I would think.

So I am unconvinced about the how accurate the location information in that study was in terms of where the greatest abundance of zebras may be found. It may have been very accurate or it may have involved a bit of misdirection. How can we know for sure. The researchers apparently relied on the collectors for the selection of collection locations.

I have a few observations about the research having spent way to much time cutting and pasting into Google scholar. If I have read things correctly, the number of fish collected during the experiment is relatively small. They observed 282 total fish and managed to collect (or at least weigh) 201 in over a year. One box of fish being illegally exported will contain maybe 100 fish or more. So the numbers observed/collected likely under represents the actual population levels. Next, it appears as if the size of the zebras collected was greater the deeper the water in which they were found. I get the impression that one of two things may be going on. One is that the zebras in general may move to shallower waters to feed, especially when younger. The other is that the it is the younger zebras which may come up to shallower waters more often.

The depth information also indicates that where zebras are collected in the greatest numbers at any of the four sites is always during the dryer parts of the year. But then the zebras have no control over the river depth. So living on the bottom when the water rises they live deeper and vice versa. The difference is that it is increasingly difficult to survey their habitat and to collect them the deeper that might be and the stronger the current. The other interesting data on this is while the numbers of fish collected was greatest at the shallowest of the sites, the biggest fish were taken at greater depths. What might this say about the normal habitat for adults who are the really the heart of the population since they are the ones reproducing? I did not see any data regarding the discovery of eggs or wigglers.

Assuming the paper is an accurate report, I have to wonder why fishermen who are risking their lives to engage in a criminal activity would be inclined to provide accurate information about their activities which might lead to losing their livelyhood and freedom. If I were a Brazilian enforcement officer and I read that paper, I would be concentrating on the areas they listed in my efforts to catch the smugglers red handed. And they were kind enough to provide pretty accurate "GPS" data on the collection locations in the study.

In the end I think that there are simply too many barriers which make it extremely difficult to do accurate surveying of zebras and their habitat. The government does not readily issue permits for the collection of these fish from what I understand. Then there are the natural barriers of seasonality and depth to complicate this. If they are deeper down, how would this be discovered?

What all of this means to me is that this paper may or may not accurately represent where the majority of zebras may be living year round. But I would also assume that given the value of the fish that the illegal trade that they would have been over collected for sure if they are easy to collect. Given that there have never been any accurate population studies at all depths to establish mumbers, we cannot know for sure where most of them may live and whether collection during the dry season when depths are less has seriously depleted populations of not.

Circling back to the original point of this thread, zebra biotopes, I can say I have never seen any reports of what other fish (not bottom dwellers) might have been observed in the same waters where and when zebras are being captured.

My primary experience, and hence knowledge of these fish, is based on their behavior in my tanks. I can make the following observations. Zebras tend to stay under cover during daylight- so they are not real fond of light. this would argue for their having a preference for darkness, i.e depth in the wild. Further, I know that new fry become very interested when the flow starts to disappear when I am cleaning tanks and filters which eventually removes all current from the tank it is also the only time I have the tank light on. It is then I see fry out and darting about. I never see adult fish doing this. Next, I have spotted my youngsters/juvies out of hiding and flying all over a tank when I was standing far enough away that they were not aware I was watching (i.e I was at least 20 feet from the tank). This happened in broad daylight and indicates to me that the younger a zebras is, the less cautious it is likely to be. In the wild, this would translate to it being easier to capture them the younger/smaller they are. However, bigger fish do have greater value.

The other thing that I am curious about is the dissolved oxygen levels involved in all of this. My understanding is that zebras need good oxygenation. Since the lowest level of DO at any location would be when the water is warmest and the current the lowest, i.e. dry season, I wonder if lower DO levels may cause zebras to move to shallower depths they are. Is is possible that, for zebras, habitat is not a constant but may be seasonally variable due to the DO levels? In the rainy season they might live deeper but, during the progression of the dry season, they migrate to shallower depths? Are the youngsters more active than the adults? If so, do younger zebras need higher DO levels? All of this interests me and puzzles me.

The one sad thing to take away from this paper is that the authors note that the Belo Monte dam is putting this species at risk. They also seem to feel that over collection may also be threatening the populations. The one positive in all this is that, between the time I purchased my breeding group in Apr of 2006 and today, a large number of hobbyists have acquired these fish and are now spawning them in tanks the world over. When I got the group I rarely saw them for sale on AquaBid, by online vendors or in stores. You usually had to know somebody to get them. Since then the number of both WC and TR zebras for sale has greatly increased, especially the latter. I am very encouraged by this because it means no matter what may come to pass in the Xingu as a result of the dam, these fish will survive within the hobby. If I understand what is happening in Brazil, there are also efforts regarding captive breeding which also have the same goal.

[racoll]

Rather than concoct a thousand reasons why the results could be incorrect, is it not easier to just accept the data at face value?

Nobody likes to be wrong about something, but sometimes I think it's actually nice to be able to reflect and acknowledge that we can learn something new and adjust our opinions accordingly.

[TwoTankAmin]

racoll- This was a nice report but it is flawed in several ways in terms of being research. I am surprised you did not see this. In any research there is a need to avoid any potential for biasing results. But then you also did not provide any support for anything, all you said was I hate to be wrong- that is some really top notch critical commentary. Please, prove me wrong in what I offered. Show me the things which I noted were wildly off the mark and unsupportable rather than what is essentially name calling. A 1,000 reasons? I am sure you counted them (insert smiley face). If I sound annoyed with your comment, it is because I am.

And then lets consider that the paper was a dissertation for a Masters degree. So it is not even a doctoral thesis nor is a peer reviewed paper which appeared in a journal. To you these may be nit picks, but for science they are not. This indicates a minimal budget being available. Normally one would expect that every diver would have had both GPS and depth instruments which would have enabled exact data on geolocation and depth for each fish spotted or collected.

Let me say here and now that none of this discussion should be taken as personal. It is not for me, what it involves is an attempt to understand the information presented and to reach reasonable conclusions from it. This requires one may have to do some "due diligence" and analysis of the data presented.

This paper relies on a number of local fishermen for a lot of the information, the same ones who catch zebras illegally. There were a number of these folks interviewed. Then some were used to do the actual observations and capture. The one thing we do know is all of these fishermen are considered criminals by the Brazilian authorities. What influence might this have had on their responses?

1. Were they paid? This could create a serious potential for bias. The paper does not mention anything about this. This leaves room for bias because to earn their money they may try to say what they think the researchers might want to hear. Most papers use some method for accounting for such potential bias and countering it. This one neither provided information that these fishermen were or were not paid nor anything to counter the potential for bias if they were. Most of the collection information relies completely on the reports by these fishermen. And the fishermen were found by one fisherman suggesting who to interview next until they started getting the same names. I wonder if any of the actual total zebra collectors may have refused to participate because they were afraid it would lead to their being caught.

2. The objectives of the study were not to determine where zebras live as a species, but to determine what effects the dam might have on them by picking several specific locations which were presumed to be especially vulnerable to the effects of the dam. This opens the door to researcher bias since it appears the authors believed that dam would be a grave threat to the survival of the species. So it becomes a bit of a leap to make species wide conclusions. This is especially true when they did not dive to full depths.

3. There is no reason given why the collection points, constituting a sample population, are representative of species wide factors. That is, they did not establish that their sample populations represent the general population. This is important in light of the fact that the biggest fish were found at the greatest depths and they did not appear go deeper than 13 m. But they did state the average depth of the river was 20 m.

4. There appear to be some contradictory statements within the paper itself. But this is based on my going though and translating a page at a time and not assembling one complete copy in English. I do not know how much time you have devoted to looking at this paper, but I have now spent at least a dozen hours. But perhaps you read Portuguese, I cannot. Here is one example:

The occurrence of H. zebra at depths ranging from zero to fifty meters, with 97% of respondents stating fishermen's preference sort by shallows. There was a predominance of occurrence in places up to 10 meters, with no record of individuals in places over 15 meters deep

from page 101

So they start by saying zebras occur from 0 to 50 m and then they say they are not found in places over 15 m. There is clearly no contradiction here is there? And I cannot fathom any reason why divers would prefer to collect fish at 5 or 10 meters over 30, 40 or 50 m (in case you missed it, that was sarcasm). Take a look at Figure 4-5 where the author shows fishermen reporting finding fish at both 15-20 m and over 20m. How can there be no record of finding zebras deeper than 15 m immediately followed by data showing they found them at over 15 and even over 20 m??? And then try adding up the percents reported in Figure 4-5. I cannot make sense of them, perhaps you can clarify this?

But the biggest problem I have is how you choose to interpret what they presented. You have considered one single fact and that is the information that the lowest depth at any site the fish were found was 2 meters. There is a lot more going on here than that one "fact". Lets start with the fact that this was at the site where the fewest fish were observed/captured- 25/283 or 8.8% of the total. And that 2 m depth was during lowest water levels for the year- the height of dry season when the total fish taken at that location was 8. So you are basing your conclusion on 8/283 fish or fewer than 3 %. The average depth for that location is shown as just under 5 m in Figure 2-3. If you look the sites at where they encountered the most fish, then the depths are greater, more like the 5 m average and as deep as 13 m.

What about all the fish which were also deeper than the average? There is no breakdown by depth in terms of collection, we get only averages. If you catch one fish at 2m and one at 6 m and one at 7 m the average depth is 5. But one could not conclude the fish live at 5 or even at 2 based on that. Numbers can be useful, but unless we can see more of the the raw data, it can be misleading to use averages or means. There is almost no statistical analysis at all in the paper. Where are the standard deviations? What does the distribution bell curve for them look like?

I may not be an expert on fish, rivers, Brazil or zebras, but I have foundation in experimental design and especially statistical analyses although I have not used these skills in quite some time. I will not argue whether or not they can spot or capture zebras in shallower water during the low water periods as they clearly can, but I am not willing to conclude this means they live shallow in general. The data presented, as sparse as it is in terms of the statistical analysis, does not support such a conclusion. And what about what Mr. Lucanis stated on FB which shortykilogyrl was kind enough to post. There are really no small dither type fish found with zebras. The reasons were depth, current and lack of cover if I understand it correctly.

And finally, why have you not commented on the quote from Ingo and Hans in the Catfish Atlas or the Lucanis statement quoted above? It seems this would have been an appropriate response instead of "accusing" me of ignoring "facts". I see a bit of "the pot calling the kettle black" here. Why have you failed to spot any of the issues I have seen? It is simple, either the things I noted are relative or else not valid issues because "insert your reasoning here". It is this lack of your providing any rebuttal at all that disturbs me. One simple explanation might have been: You translated this statement as saying X, but in the real world of the Portuguese language as opposed to what Google translate spit out its meaning is different.

What I felt was actually the single most interesting piece of information presented in the entire study was in the section regarding the interviews of the fishermen. They stated that they found eggs/fry year round. If this is accurate, then it would suggest that there is no seasonality involved in spawning. This gives a potential explanation for why those of us who keep zebras and have them spawn will often fail to get spawns from doing the dry/rainy season simulations. It may be why we find that ignoring them for many months on end often results in "surprise spawns." And finally, it may mean that changing the whole seasonality effects in the Volta Grande due to the dam may not cause the extinction of these fish in the wild. But only time will tell. But, at least now there may be cause for hope.

Shortykilogyrl, I apologize for hijacking your thread.

racoll- I see no point in further discussion here until you respond to at least few of my more salient observations and comments with similarly referenced information and data. If all you wish to contribute is the comment you made above, then there is little reason for continuing the discussion, at least on my part, beyond this post.

[TwoTankAmin]

As is my habit to return to threads when I have something new and relevant to add, I would like to point out a paper, from 2014, I have found. What it does is to support what racoll wrote as well as some of what I wrote. Basically, zebras live deep and shallow and in both faster moving and slower moving waters. It seems to depend on the age of the fish and time of the year. So I am not sure it is even possible to say at what depth they "live" if it is not an average or at least calender and age delineated statistic.

BELO MONTE AND THE LOCAL DEPENDENCY ON ORNAMENTAL FISH

Impact of hydroelectric dam Belo Monte in the Xingu River on ornamental fish
species, local fishermen and local traders

R. Diemont
Forestry and Nature Conservation
28th August 2014
Velp

Although stingray Raia Pintada (Potamotrygon leopoldi) gives the highest price for fishermen, it was never mentioned as preferred species, because of the risk of being pinched by its sting and the erratic pattern of demand from local traders due to quotas. Acari Zebra (Hypancistrus zebra) is the next most expensive fish and highly preferred by both fishermen from Altamira as fishermen from Muratu. Most important reason for this preference is that this fish is the only fish which gives a high price throughout the whole year, especially in the summer (in which the price of the ornamental fish drops as it is easier to collect ornamental fish when the water level is less high and more fishermen become active). Acari Zebra (Hypancistrus zebra) is not frequently caught by fishermen of Altamira, because this fish is not allowed by law to collect. Legal local traders refuse to buy this fish, as it is very risky for their businesses when control takes place. Fishermen of Muratu do collect this fish often and sell this fish to clandestine local traders. Next to the high price, fishermen mention that this species is not only found water with a high current, but also in calm, shallow waters, which makes it less dangerous to capture this species (compared with other species).

Clearly, zebras are not found only in deeper or in fast flowing waters. So, in that respect, I have to say I was mistaken. However, I am also curious about a few things. I have read that fry and young zebras need more vegetable matter in their diets at an earlier age. They cannot find this in deeper water. Moreover, I wonder what the distribution is by size/age in relation to the depths where they are found. Logic would suggest that the greatest risk for predation would be from coming closer to the surface. This would be mitigated by size, i.e. a smaller zebra can find more places where it can fit to hide as well as being harder to spot.

What I do know from personal experience is when my Hypancistrus have fry, during weekly tank work I regularly see newborn and smaller fish come out of hiding. It's almost as if the loss of current as I systematically take filters offline to clean them make these young fish curious and come out of hiding. This habit does not persist for very long. But I do enjoy seeing it when it does. This suggests to me that in the wild younger zebras may not have learned to "fear the shallows."

Are the zebras which get collected from shallower water living where they are caught all the time or are they coming up from deeper water during the day and going back down at night? (Are zebras even collected at night to be able to know the answer?) And then, if they are living in the same spot year round and the water levels go up and down with the season, how appropriate is it to use specific depths when collected vs average depths?

Aside from the above information, this article has a lot of interesting information about zebras:

Habitat summer "Remansos "and "poços "
Habitat winter "Remansos " and "poços ". These locations differ per season, as the river contains less water in the winter period. Acari Zebra follows this fluctuation
Reproduction period (spawn and juveniles) August - October
Reproduction habitat: eggs "Remansos " and "poços ". Eggs are spawned in holes and fractures of rock formations and "mocororo" rocks
Reproduction habitat: juvenile fish "Remansos " and "poços ". The juvenile fish remain in and around the holes and fractures of rock formations and "mocororo" rocks
Alimentation summer Living algae on stones, small crustaceans, and a white fresh water sponge with microorganisms
Alimentation winter Living algae on stones , small crustaceans , and a white fresh water sponge with microorganisms
Current (1 = 'very strong'; 5 = 'stagnant') 3
Minimum depth (m) summer 0.05
Maximum depth (m) summer 40
Minimum depth (m) winter 1
Maximum depth (m) winter 50

Already noticed impact on this species

This species already occurred less before the dam constructions started, because of over exploitation and uncontrolled illegal trade. The past four years the dam is built on the most important fishing location, where this species occurred abundantly. Down stream the dam, juveniles and adults are weaker nowadays; individuals die faster, their skin turns red and the tail drops off after being captured. Another problem down stream is the sediment covering the living algae, which is an important food source for the fish.

All fishermen believe the dam will have a negative influence. The dam will provoke the extinction

For those of us who are metric deficient, that .05 meter minimum depth in summer is just a hair under 2 inches. Of course, the maximum depth at 40 meters would be about 131 feet and in winter it becomes 164 feet deep. I wonder how they know these are the maximum depths? How many divers go down 131 let alone 164 feet in fast flowing dark water?

(Edited to correct layout of the quote)

[Jools]

If you can collect zebras in a few inches of water, I am certain they would have been fished out seasonally back in the "good old days". That they take a fair bit of effort even to observe in the wild ("mine" was about 3m down) helped them.

Interesting data that they spawn only at a given time, which is the height of the dry season. I think it would be hard to find spawning fathers in the height of the wet season (before the dam).

Jools

[TwoTankAmin]

I doubt one could ever collect lots of zebras in 2 inches of water. However, I can see a very young zebra ending up two inches deep on a rock looking for algae. And all it takes is for one zebra to be spotted this way for it to be possible to state that have been observed that shallow. I find it much harder to believe somebody caught or spotted one 150+ feet down in the dark and current.

If they spawn in the wild anything like they do in tanks, then they are spawning at other times than Aug.- Oct. (or its equivalent in a captive setting). I keep several Xingu Hypan. species and they almost never are all spawning at the same time even though tank conditions are similar for them all.

[Raul-7]

I keep mine with Pencilfish [Nannostomus marginatus and N. unifasciatus] and Hatchetfish [Carnegiella strigata and C. schereri] without issues and the L46 breed. Both of these genera of fish are docile and rather shy. They do not compete with the food that sinks to the bottom the way Tetras do. Then I have Blue Neocardina shrimp for cleanup.

And note my aquariums mimic the area; large rocks, painted black on 3 sides, sandy bottom, no plants, oxygenated water and strong flow.


They do just fine.