Scleromystax barbatus

[AndiH]

I received the S barbatus about 3 weeks ago and they really did well through the shipping with only one appearing very stressed. There were 8 in the shipment so I sold 2 to the LFS since I didn't feel I had room for that many.

They're currently in a 29g with some harlequin rasboras and 3 mollies as well as a few ghost shrimp.

The temperature in the tank was initially around 74 but during a warm spell it reached up to 78 for several days (with heaters unplugged just to make sure!). They slowed down a bit, but otherwise did very well. With the return of cooler temps, the tank is again around 72-74 and they are constantly moving about once more.

I have well water that is high in iron and the pH is high, pushing 8.6 without driftwood and plants, but with them it is around 8.2. My water is soft as it goes through a conditioner though I haven't really tested the hardness at all.

If anything major changes, I'll drop a reply off.

[MatsP]

Did you really mean to post this in the "Bugs" section - I can't see that you are suggesting anything should change on the site - if not, just say so, and I'll move it to "Corydoras" section...

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Mats

[AndiH]

I meant to post here as Jools said to do in this thread: http://www.planetcatfish.com/forum/view ... =2&t=29849

[MatsP]

Ah, ok.

By the way, I'm a bit confused with regards to your pH/hardness statement. In general, soft water is acidic (pH less than 7), and hard water is alkaline (pH greater than 7).

I personally think that keeping a species for less than a year in any particular condition is not a good indication of what water conditions it requires [at least if it's a relatively long-lived species]. Fish will regularly tolerate temperatures quite a bit outside their "recommended" temperature - but they will not necessarily thrive under those circumstances. You have already said that they clearly prefer a lower temperature.

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Mats

[Mike_Noren]

You have already said that they clearly prefer a lower temperature.

I suspect this thread was referred here because they probably don't prefer a lower temperature. S. barbatus is a fully tropical species, from the lowlands north of Rio de Janeiro.

[Jools]

This may well be true, but at least from my experience, they tend to die if kept at higher than about 78F for much time. Steve Pritchard went with sands in the late 70's I think to collect this species and brought them home and bred them. I think his opinion on the temp thing might be a good idea to seek?

Jools

[Mike_Noren]

S. barbatus home waters show temperatures ranging from 16 to 30 celsius, ie pretty normal tropical temperatures, and it is found syntopically with normal tropical species such as Parotocinclus maculicauda, Hypostomus punctatus, and Rhamdia quelen.

[AndiH]

Mat, I've read that elsewhere about water hardness and pH, but all I can do is tell you what repeated testing has shown me regarding pH and the fact that the water softener is running as demonstrated by appliances throughout the house lol. Regarding the keeping of them a year, I understand your point but thought I'd mention how things stand at this time and keep it updated with any changes. If that is against usual protocol, I apologize. Its just the way my mind works best

[MatsP]

We probably should split this off, but I'll keep it here until it gets too messy: using a water softener for aquarium water is pretty bad - the softener replaces the "hardness" in the water with "salt" [unless it's a proper RO and/or deionization unit - which is certainly not what people have in their homes unless they really do need to remove all content in the water]. Traditional home water softeners are "ion exchange units", so they take on one type of ion and replace it for another - commonly substituting calcium/magnesium for sodium and carbonate for chloride.

Can you please measure:
KH (Alkalinity/Carbonate hardness)
GH (General hardness)
pH
Also, leave the water to stand for 24 hours and measure both again.

For all measuring, beware that paper strips are pretty much useless for anything other than for quick "is it really bad" detection. Drip tests are OK for most purposes, but pH measuring with drip tests is also often a bit off - a pH meter is much better, but will cost a fair bit more than a good test kit - in this country they are around £20-30 for a basic model - that's about US $30-50 - and don't forget to get some calibration solution so that you can make sure it's calibrated.

Ideally, you should also measure the "TDS" or "Electrical conductivity" of the water - for this you definitely need a meter [or boil a huge quantity of water off until you get the dry residual content - but to measure that accurately will require a good set of calibrated scales with high enough precision to measure whatever you are boiling the water in and get a repeatable measure within tens of milligrams]. The meter here isn't very expensive, around $20. Or you can probably take a water sample to your LFS for testing the TDS value - ask before you go!

Also, if you have access to water before it's gone through the softener, do the same tests on that.

Of course, the fact that your water has been through a water softener will probably affect the hardness and it may well have altered the
constituency of the water so that it's technically soft, but it won't have altered the pH - it is just more salt and less calcium/magnesium...

For fish that like soft water, my understanding is that the electrical conductivity is a more critical factor than the type of ions - whether they are "hardness" or "common salt" ions doesn't really matter that much - in fact, to some extent, "common salt" is worse!

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Mats

[Bas Pels]

Actually, I think the pH might have been altered too

As MatsP described, carbonate is exchanged for chloride. Carbonate is a rather good base, chloride is a very waek one

As a base is the opposite of an acid, I would think remouving a strong base for a weak one would make the water more acidic

@ the type of ion, fish liking soft water are adapted to water with little dissolved solids in it - charged ones and uncharged ones both. However, in natural circumstances, there is not much uncharged stuff dissolved, and therefore we choode to ignore that - measuring only the charged ones, with a conductivity measuring device

still, fishes need calcium for their bones, and therefore the conductivity a softwater fish faces would better be calcium - in the correct amount, obviously - than sodium

[AndiH]

Can you please measure:
KH (Alkalinity/Carbonate hardness)
GH (General hardness)
pH
Also, leave the water to stand for 24 hours and measure both again.

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Mats

I can certainly run those tests, both pre-softener and post-softener. I use the API master kit and have the seperate GH and KH tests as well. I'll see if the local LFS can run the other tests, but being in the boonies I won't hold my breath.

[sterba]

In discussing S barbatus,I have kept them for about 5 years ,and have raised in excess of 3000 fish.I have tap water with a microsiemen typically over 300.Have never been succesful hatching eggs in this water.I spawn them in RO water from 30-120 microsiemens and temps from 64-72 degrees F.

[sabbath]

I'd like to pipe in and agree with what sterba said. I have bred lots of them and used water with essentially the same chemistry and temp. Cool, soft and acidic!

[Jools]

In the last fortnight, I've raised the temperature of my group to 78F and they have stopped spawning. No signs of ill health, but then I will be dropping back to unheated ASAP. I've not heard back from Hans or Steve yet on this.

Jools

[Jools]

I'd be happier with 16 to 22C, but above 22 doesn't seem right for captivity unless, like the wild, there is a lot of oxygen. It is possible the lack of DO is the factor here and not the heat - bearing mind mind most people keep "corys" in little to no current. Mine are still not spawning at 78F (in current), so will drop the temp again.

Jools

[Jools]

Scleromystax barbatus

currently has 16 - 19C.

Jools

[Mike_Noren]

I still have a really hard time believing that 16 - 19 celsius is an optimal temperature range for a tropical lowland species from small, vegetated, slow-flowing waters.

[Jools]

Which is why I suggested 16-22C [61-72F]. What source please for data on slow moving waters? It's a good point about optimal though, I've not seen any problem with them at around 64F, but my main concern is to get across that they do not do well at all above 78F or so, especially younger fish.

So, maybe, 20-25C [68-77F] with some text in there to explain the points?

Jools

[corybreed]

Jools

I have kept barbatus for many years. I have a few groups now. My fish room gets hot in the summer and they are never happy with the warmer temperatures. I do regular water changes with cooler water to get them through the summer. Once the weather gets cooler in September they should start spawning again. In the winter the water temperature can get as low as 66F. A friend of mine from Brazil has collected barbatus in Rio not very far from the beach. I will ask him to give me specific water parameter information.

Mark

[Mike_Noren]

What source please for data on slow moving waters?

Upon re-checking:
http://www.biotaneotropica.org.br/v10n2 ... 0022010+pt
I found that it actually lives in moderate to strong current.

However, I also found this:
"Corydoras barbatus occupied almost exclusively the stream bottom mainly the right edge, in litter and trunk/branch substrate type and waters whose current was lower than 0.25 m.s-1"
http://www.scielo.sa.cr/scielo.php?pid= ... ci_arttext

[Jools]

OK, again, maybe, 20-25C [68-77F] with some text in there to explain the points? Can one of the catelog data team weave that in?

Mark - your contacts feedback would be useful.

Jools

[CoryWally]

Hi Jools,
Wasn't sure if it was this Mark you wanted some feedback from!

Anyway, Having kept and bred barbatus and 8 other Scleromystax sp. for the last 10 years, I'll offer my tenpeneth-worth.

My barbatus are generally kept at between 55 - 65f over winter (from around November to March), but up to 78f (or even higher for short spells) in the summer. I find the optimum breeding temps are when the range is between 68 - 76f. I've had close-to-death experiences if the temp exceeds 80f for a few days, when drastic water changing is required. They definately need highly oxygenated water - which of course is facilitated by cooler temps.

I don't necessarily chose to maintain the fish at these temp ranges, but my fish house dictates that the lower racks are much cooler in the winter! I think it suits the Scleromystax and other more southerly Corydoradinae perfectly.

Spawning activity increase as the temp increases from the mid 60f's up to the optimum range. Below the mid 60's, the barbatus don't appear to show much interest in spawning but will feed quite readily and exhibit other normal behaviour. Male aggression appears diluted at lower temps also. Into the mid 70's, males appear to be always in spawning colours and regularly spar with each other - which must reduce their vigour in the long term.

Spawning is usually witnessed as the temp increases following a cold water change. However, in the optimum range, spawning will usually happen regardless. I would suggest that the intialy trigger is the rise in temp (not the lowering by the cold water), but then that single trigger can lead to multiple spawning events. The same effect is witnessed if the fish are moved from cooler tanks to warmer tanks.

Eggs hatch best at around 72f and there appears to be reduced hatching around 76f. Fry development is optimum around 72f also.

Other Scleromystax have different preferred ranges, e.g. kronei and C112 appear to spawn in much cooler conditions - preferentially 66-68f.

Hope this is useful,
Mark.

[Jools]

Wasn't sure if it was this Mark you wanted some feedback from!

It was Mark Soberman, but as he's not come back, then I'd say your feedback is really welcome as it is hard data. I'll weave some of this data into the page which, I think (hope) will better reflect captive requirements.

Many thanks,

Jools

Link for my own uses!

Scleromystax barbatus

[Jools]

I've now updated the page, text and figures. Mike - does that sit within what you're comfortable with?

Jools

[MatsP]

I've fixed a tiny typo, but otherwise it looks like you've captured Mark Walter's discussion fairly well.

Edit: Also added translation of temperature between F/C temperatures in the update.

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Mats

[CoryWally]

I've fixed a tiny typo, but otherwise it looks like you've captured Mark Walter's discussion fairly well

Hey Mats,
Not one to be pedantic but apostrophe comes after the s in my surname (if needed at all). I'm Walters not Walter.

Cheers,
Mark