Electric catfish with bleeding fins

[Lycosid]

My juvenile electric catfish appears to have streaks of blood in his fins. They are not evenly distributed but in spots - there's currently a spot in the lower middle caudal fin, for instance. While these areas seem to be longer along the fin rays than across fin rays they don't necessarily go end-to-end, or even start from the proximal end of the fin ray. My student assistant who cares for him and myself are in some disagreement as to whether the blood is getting fainter, staying the same, or perhaps staying about the same but shifting in location.

When we discovered this I immediately told my student to do a large water change so I don't have any useful water parameters from before the incident (we did about a 50% water change). The tank is quite large for the fish (60 gallons for a single 4 inch fish) and filtered with a HOB sized for the tank, not the fish. Tank furniture is sparse - two PVC tubes that he's had in there for more than a month. He hasn't had any live food in the tank that he hasn't killed almost immediately in several weeks so I don't think he's been injured by furniture or food.

However, he may be a slightly more stressed-out fish since he gets weighed weekly in a much smaller container. My student took photos of him in the container up close but I haven't gotten those yet and I don't want to wait on those.

Any thoughts?

[Bas Pels]

Assuming the spots are not similar on both fins, I would asume an accute ammonia problem - which needs a firm waterchange immediately

240 liters of water would be enaough for a 10 cm fish, but if the tank is not really cycled, the amount of ammonia eating bacteria can still be low. Another option can be, an electric cat is a predator, and predators don't eat dayly. Therefore the ammonia excreted can also mostly be low, but high when fed.

If this is the case, it would be better to feed more often, smaller portions

[Lycosid]

The tank has been cycled for a while now - he's been in it for months - but I'm not convinced that the filters are the best. (I also think there was a day when the filter got left off after a prior water change.) I've been gradually changing out the filters but maybe I need to up my schedule on that.

Thanks for the advice.

[Viktor Jarikov]

Photos could be crucial.

What live foods is it feeding on?

What are the water parameters? Ammonia, nitrite, nitrate in ppm, pH, temp, hardness? Are the latter three stable? Is aeration adequate? What's the lighting like? Any other sources of stress except weekly weighing?

Replacing half of the tank water does not make parameter readings moot, IMHO. For instance if your ammonia was 0.25 ppm, that means it was 0.5 ppm before the water change.

[Lycosid]

I can get photos and current water parameters tomorrow.

The lighting is relatively low - he's got two long tube shelters to hide from the light in and the room is only lit when someone is working in it, although the blinds on a window across the room (but not a straight line across) are always half-open because we are growing some plants on that window sill. There's also a snake cage in the opposite corner of the room with a lamp on it. No other light. It's a bare-bottom tank with no plants.

He's eaten a few small feeder minnows from the pet store but the bulk of his diet is sinking carnivore pellets. I'm trying not to feed too many minnows so as not to introduce disease while I get a guppy breeding tank up and running.

Aeration is provided by the same filter that I don't like. The replacement I've been working on will include an airstone. I'm not sure the filter is bad, per se, it's just an old lab hand-me-down that I don't trust. I was left a lot of tanks and old tank equipment by my predecessor and a lot of it is older, less efficient models, banged up, or, in some cases, terribly, terribly put together. In my initial testing I turned on one device which promptly exploded, frying everything attached to that power strip as well.

[Annabellam]

Good you are introducing all the changes even with the filters - better be wrong than sorry. I think it's stress related so with the changes, a better environment should help it get back to normal.

[dw1305]

Hi all,

I can get photos and current water parameters tomorrow.

A photo will be useful.

...... It's a bare-bottom tank with no plants........

Others will disagree, but I think keeping a large carnivorous fish in a tank without plants, or substrate, is a recipe for disaster.

The waste in the tank you really need to be concerned about isn't the faeces etc that you can see, but the invisible ammonia (NH3) that is constantly diffusing from the fishes gills. The more protein a fish eats the more ammonia that needs to be processed by the filter.

If you have a substrate, and particularly floating plants, the filter is no longer a single point of failure, and ammonia levels should fall.

Have a look at <"http://plecoplanet.com/?page_id=829 "Aeration and dissolved oxygen..."> I wrote it for rheophilic plec keepers, but it is relevant to most fish keeping.

Aeration is provided by the same filter that I don't like. The replacement I've been working on will include an airstone.

I think we need to know a bit more about the filter.

cheers Darrel

[Viktor Jarikov]

E-cats don't need live feeder fish at all IMHO. Unless, of course, you are trying to prove some point. It's hard to say what you are doing with this fish, research of some sort?

E-cat I've had and those I've read about gobble up almost any non-live food with or sometimes without any training (read fasting). If you introduced a single feeder fish from an LFS into its tank, we already cannot discount a possibility that it brought a pathogen into the tank. Feeder fish are mass-produced and kept in filthiest of conditions.

[Lycosid]

Alright, here's what everyone's been asking for.

Water parameters: 0 ammonia, 0 nitrite, 0 nitrate. I was so suspicious of this (although we've been doing daily water changes) that I compared the ammonia test tube to an ammonia test of my own tap water and they looked identical. (I never think test tube colors look all that much like colors on paper.)

My student's photos of the fin problem have never come through. He's tried to send them to me three different ways but no luck.

However, the catfish is in a new tank. The tank is because I wanted a major filter change and I didn't have enough foam to do what I wanted in the tall tank.

Bearing in mind the comment about plants and gravel and our own research need NOT to have too many things in the tank I did a Mattenfilter across a 20 gallon long and stuck the heater behind it. I also added a potted plant from a well-cycled tank (the gravel dripped green liquid when removed) behind the filter, facing the window. Since the new foam came from a "dead" tank (no fish - a student had been testing DIY filters in the tank in a fishless cycle but they hadn't done anything to it since winter break) I also added in the original filter. I also used his tank water to fill the tank to avoid temperature shock.

The catfish hasn't eaten in a while which may help with ammonia. He's due for another feeding soon so I'll probably just give him a few sinking carnivore pellets.

He will eventually switch back over to live prey. Our research is on predation ecology and so he needs to act as a predator or we don't get any observations. However, I've sourced some healthy spare guppies from someone local who is finding that fancy guppies breed a little faster than they wanted.

[dw1305]

Hi all,
I've just noticed your user name, do you have a scientific interest in "Wolf" Spiders?

Water parameters: 0 ammonia, 0 nitrite, 0 nitrate. I was so suspicious of this (although we've been doing daily water changes) that I compared the ammonia test tube to an ammonia test of my own tap water and they looked identical. (I never think test tube colors look all that much like colors on paper.)

Yes, you definitely won't have 0ppm NO3-. Monovalent anions can be problematic to test for, mainly due to interference from other monovalent anions.

The blood streaked fins are highly suggestive of damage from high nitrite levels (NO2-), and therefore insufficient biological filtration.

Do you have access to an analytical lab. somewhere else in the University? If you do they may have ion selective electrodes which are more likely to give you an accurate result. I don't do any regular water testing, but I've run the tank water through the water testing analytical lab on the ends of runs of other samples.

I use an adapted Lemna bioassay (http://www.mobot.org/jwcross/duckweed/duckweed.htm) to estimate the nutrient status of the tanks. Although this might seem less scientific than water testing, it has proven to be very effective. I've called it the "Duckweed Index" (http://www.planetcatfish.com/forum/view ... hp?t=36231) and I know that it has now become more widely used.

Bearing in mind the comment about plants and gravel and our own research need NOT to have too many things in the tank I did a Mattenfilter across a 20 gallon long and stuck the heater behind it.

I think matten filters are the way forward for you. Have you read Stephan Tanner's article on Biofiltration? It is a good read <http://www.swisstropicals.com/library/a ... iltration/>.

I also added a potted plant from a well-cycled tank (the gravel dripped green liquid when removed) behind the filter, facing the window. Since the new foam came from a "dead" tank (no fish - a student had been testing DIY filters in the tank in a fishless cycle but they hadn't done anything to it since winter break) I also added in the original filter. I also used his tank water to fill the tank to avoid temperature shock.

OK. I would strongly recommend you add some floating plants to your tank, they aren't going to effect your experimentation, but they will have a dramatic effect on water quality. Floating plants have access aerial CO2 and aren't carbon limited so can make optimal use of the nutrients in the tank water (dependent upon "Liebig's law of the minimum" (https://en.wikipedia.org/wiki/Liebig's_ ... he_minimum)).

Plant/microbe filtration systems are much more efficient than "microbe" only systems at biological filtration, this is because the plants actively uptake NH4+, NO2- and NO3- from the water (http://www.bookmasters.com/marktplc/ima ... ebsite.pdf), and because they increase the area and diversity of habitats for nitrifying organisms (http://journals.plos.org/plosone/articl ... ne.0113515).

Recent work, using the RNA markers to look for ammonia oxidising genes in filter based micro-organisms, has shown that Ammonia Oxidising Archaea are much more important than was realised. Have a look at <"Aquarium Nitrification Revisited: Thaumarchaeota Are the Dominant Ammonia Oxidizers in Freshwater Aquarium Biofilters" (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3156731/)>.

cheers Darrel

[Lycosid]

I've just noticed your user name, do you have a scientific interest in "Wolf" Spiders?

Yes. I do a variety of predation ecology experiments and at one point our lab used a lot of lycosids as the predators (frequently on acridid grasshoppers). I've now moved on to more salticids and, obviously, some catfish. It took the university a while to decide that we had all our permits in order for vertebrate work, even though the only animals that die in my work are eaten by other experimental subjects.

Yes, you definitely won't have 0ppm NO3-. Monovalent anions can be problematic to test for, mainly due to interference from other monovalent anions.

I assume "0" in this case means "limits of detection for this test kit". I notice that for nitrate its steps were much larger than for the other nitrogenous wastes.

Do you have access to an analytical lab. somewhere else in the University?

You're talking to our entire organismal biology faculty right now. We're small. I've asked one of our chemists (i.e., I asked half the chemistry faculty) about this and she said they might be able to figure something out but give her a month.

I think matten filters are the way forward for you. Have you read Stephan Tanner's article on Biofiltration? It is a good read <http://www.swisstropicals.com/library/a ... iltration/>.

Yes, I did read that. I've been very interested in DIY filters for a while and have really liked Mattenfilters as the major drawback is ugliness and in a lab that's simply not something we worry about while the upsides are huge. I actually have one of my best tanks running off a "bucket filter" which is essentially an air-driven corner Mattenfilter mounted in a square bucket which lets me place the "corner filter" in places other than the corner of the tank. (I'd do all four sides of the bucket except that the filter foam is a lot easier to seal around the edges if I just bend one large piece of foam against two "windows" in the bucket.)

I would strongly recommend you add some floating plants to your tank, they aren't going to effect your experimentation, but they will have a dramatic effect on water quality.

Well, they actually would interfere with some of the above-tank sensors getting a straight line on the tank if they were in the main chamber but your earlier comment about duckweed (which I have plenty of) makes me think I should drop some behind the Mattenfilter.

Ironically, I've been keeping fully enclosed aquatic ecosystems for years now (I have once still running that I started halfway through grad school) and so I should know about how great plants are at biological filtration. I was overly-trusting in the ability of a HOB and a large water volume to take care of things once I decided that the sensors couldn't deal with plants. (Admittedly, I was always planning to eventually do a Mattenfilter. I simply wanted to wait for a particular student assistant to be free to work on it with me because I could then have sent her off to make one for each tank.)

HOWEVER the big take home is that the catfish appears to be fine as of today. No blood. I'm currently assuming that there was a big ammonia pulse and that a lot of water changes dealt with it. I'll monitor and feed carefully moving forward but hopefully changes to the filtration will help with that. Thanks for all the thoughts everyone - I think I'm coming out of this with a much better filter system that I originally had planned.

[dw1305]

Hi all,

Yes. I do a variety of predation ecology experiments and at one point our lab used a lot of lycosids as the predators (frequently on acridid grasshoppers). I've now moved on to more salticids and, obviously, some catfish. It took the university a while to decide that we had all our permits in order for vertebrate work, even though the only animals that die in my work are eaten by other experimental subjects.

I should imagine salticids would be an interesting area for research. It's not my field, but I love watching the small European Zebra Spiders (http://www.eurospiders.com/Salticus_scenicus.htm) hunting.

Yes, you definitely won't have 0ppm NO3-. Monovalent anions can be problematic to test for, mainly due to interference from other monovalent anions.

I assume "0" in this case means "limits of detection for this test kit". I notice that for nitrate its steps were much larger than for the other nitrogenous wastes.

Do you have access to an analytical lab. somewhere else in the University?

You're talking to our entire organismal biology faculty right now. We're small. I've asked one of our chemists (i.e., I asked half the chemistry faculty) about this and she said they might be able to figure something out but give her a month.

No you will definitely have a measurable amount of NO3, the problem is with the analytical method. Unless you have analytical grade kit, it is quite difficult to get accurate and repeatable figures for NO3-. One of the problems is that nearly all nitrate compounds are soluble, so you have to reduce the NO3- to NO2- before you can use colorimetry (or visible spectrum spectrophotometry).

I would strongly recommend you add some floating plants to your tank, they aren't going to effect your experimentation, but they will have a dramatic effect on water quality.

Well, they actually would interfere with some of the above-tank sensors getting a straight line on the tank if they were in the main chamber but your earlier comment about duckweed (which I have plenty of) makes me think I should drop some behind the Mattenfilter.

Ironically, I've been keeping fully enclosed aquatic ecosystems for years now (I have once still running that I started halfway through grad school) and so I should know about how great plants are at biological filtration. I was overly-trusting in the ability of a HOB and a large water volume to take care of things once I decided that the sensors couldn't deal with plants. (Admittedly, I was always planning to eventually do a Mattenfilter. I simply wanted to wait for a particular student assistant to be free to work on it with me because I could then have sent her off to make one for each tank.)

HOBs are usually good, because the filter media remains oxygenated much better than it would in a canister filter.

Floating plants behind the Mattenfilter are fine. You might be able to add a terrestrial plant as well, Epipremnum aureum "Pothos" (https://en.wikipedia.org/wiki/Epipremnum_aureum) is difficult to kill, and works well. You can root the cuttings in the tank. Most Aroids (Like Monstera or Philodendron) will work.

HOWEVER the big take home is that the catfish appears to be fine as of today. No blood. I'm currently assuming that there was a big ammonia pulse and that a lot of water changes dealt with it. I'll monitor and feed carefully moving forward but hopefully changes to the filtration will help with that. Thanks for all the thoughts everyone - I think I'm coming out of this with a much better filter system that I originally had planned.

Good, that sounds a likely explanation. Things should be OK from now on.

cheers Darrel

[Lycosid]

I should imagine salticids would be an interesting area for research.

They are, and that's part of their usefulness. It's easy to get research assistants who want to help out with them. See also: electric catfish. Since my contract is mostly teaching I'm pretty actively encouraged to make sure my research involves undergraduates.

No you will definitely have a measurable amount of NO3, the problem is with the analytical method.

I guess the question is "Should I care?" I mean, if I were interested in nitrogen metabolism I would but as far as fish-keeping is concerned is this a problem?

You might be able to add a terrestrial plant as well, Epipremnum aureum "Pothos" (https://en.wikipedia.org/wiki/Epipremnum_aureum) is difficult to kill, and works well. You can root the cuttings in the tank.

I have a LOT of pothos kicking around lab. I've actually been using some in another tank while we wait for the botany class to set up an experiment using them. I should have enough spares to use in the electric catfish tank as well.

[dw1305]

Hi all,

No you will definitely have a measurable amount of NO3, the problem is with the analytical method.

I guess the question is "Should I care?" I mean, if I were interested in nitrogen metabolism I would but as far as fish-keeping is concerned is this a problem?

People will differ in their opinion.

I just use the Duckweed Index as a visible indication of nutrient status, it works really well. Because plants need about x10 more nitrogen (N) and potassium (K) than phosphorus (P), and more phosphorus than any of the other nutrients, if you plants are growing strongly and are a vibrant dark green, then you have a lot of nitrogen, which the plants are converting into photosynthetic proteins. When you harvest the plants you remove that nitrogen from the system.

Originally I started looking at relatively accessible ways of analyzing aquarium water, that would give reliable and repeatable results over a reasonable range of pH, hardness, nutrient and conductivity levels. It pretty soon became apparent that this isn't a realistic option for most hobbiests. It is possible, but you need some knowledge of the scientific method, a lot of time and some fairly expensive equipment.

The end result was that the only meter, or test, where you could dip the meter in the tank, without calibrating or buffering before every use, that fulfilled "the range of water types" criteria, wasn't expensive to run in terms of consumables and was reasonably cheap to buy was a conductivity meter. It isn't the the parameter that you would most like to know, but that was just where we ended up.

I knew that there were techniques for assessing at water quality that relied on the response of an organism, or assemblage of organisms. We used some of these already. I also knew that you plant/microbe biofiltration is very effective at dealing with organically polluted waste water (quantified using a 5 day BOD test).

Using BOD isn't a realistic option for aquarium water testing, but using modified bio-assay, biotic index and bioremediation techniques are. That is why I started suggesting using floating, or emergent, plants for both bioremediation and as a biotic index. I also measured conductivity when the tanks were in a good condition and used that as a datum.

Originally I used Duckweed (Lemna minor) hence the "Duckweed Index", but it doesn't do well in water that is low in pH and/or nutrients, so my "Duckweed" of choice is now Frogbit (Limnobium laevigatum).

cheers Darrel

[Lycosid]

Any thoughts on using Eurasian millfoil (Myriophyllum spicatum) instead of duckweed? That's locally invasive around here and I have some in a water sample if it would work better than the duckweed.

Either way, it sounds like I should use some nice, removable floating plant.

[dw1305]

Hi all,

Any thoughts on using Eurasian millfoil (Myriophyllum spicatum) instead of duckweed? That's locally invasive around here and I have some in a water sample if it would work better than the duckweed.

Either way, it sounds like I should use some nice, removable floating plant.

Ideally it needs to be a floater so that it has access to aerial CO2, but I've used Ceratophyllum demersum (also referred to in Diana Walstad's "Ecology of the Planted Aquarium") successfully, so I would have thought Myriophyllum spicatum should do. It is native in the UK, and not invasive here.

cheers Darrel

[Bas Pels]

In Dutch aquariumbooks European Myriophyllum are said not te be suiteble for a tank. Most likely because of the temperature.

It cannot be because they need so much light - the sun is in the tropics much brighter than here. Still, I think a Myriophyllum from Spain might have much better chances than from thew Netherlands - Spain is over 1000 km more south, and on average 4 or 5 degrees C warmer

[dw1305]

H all,

In Dutch aquariumbooks European Myriophyllum are said not te be suiteble for a tank. Most likely because of the temperature.

It cannot be because they need so much light - the sun is in the tropics much brighter than here. Still, I think a Myriophyllum from Spain might have much better chances than from thew Netherlands - Spain is over 1000 km more south, and on average 4 or 5 degrees C warmer

I think that makes sense, a lot of "cold water" plants aren't happy warm long term. Ceratophyllum would work. Tropica sell a version from S. America in Europe (Ceratophyllum demersum "Foxtail" (http://tropica.com/en/plants/plantdetai ... APOR)/4434)) not sure about in the USA, but it is native plant to the USA (http://www.ecy.wa.gov/PROGRAMS/wq/plant ... ntail.html).

Amazon Frogbit is my floater of choice.

cheers Darrel

[Lycosid]

Ok. I may try a few of the floaters I have available and see who thrives. I don't know if I have anything specifically tropical that floats, but I'll also keep an eye out at fish stores.