One of my corydoras died - opinions

[EdWalker]

Hi,

I have been lucky so far I suppose in the sense that I have lost very few fish in my time in the aquarium hobby.

And the one thing I want to make sure of is that I know what it is that kills the ones that I have lost. Yesterday, I noticed that one of my albino corydoras was a very bright pinkish color on his back end. Half of his tail fin was gone. I *assumed* it was a bacterial infection and quarantined him. It is a 10 gallon quarantine and I dosed Melafix for that amount.

This morning the little guy/girl was gone.

Anyway, have any of you folks had a fish die from the few symptoms I described? Just want to see if I can pinpoint what it was.

Currently, I only have the test for ammonia and I have .25 in the tank. I dose every day with Prime.

[Lycosid]

Currently, I only have the test for ammonia and I have .25 in the tank. I dose every day with Prime.

I'm sorry to hear about your cory. I haven't kept cories (it's happening soon, though) so I can't address that issue, but this comment about ammonia is confusing to me. Are you using Prime to bring down the ammonia level in the tank? Is this alongside of or instead of filtration and water changes? I use Prime (or similar water conditioners) only on new water that I am adding to the tank to dechlorinate it. Prime seems to have a de-ammonifier in it as well because dechlorinating water treated with chloramine actually generates ammonia, and so Prime also treats the ammonia.

The safe level of ammonia is 0 (not that there's any such thing, but the levels in my tanks are undetectable unless something is badly wrong). A consistent ammonia reading seems worrisome.

[dw1305]

Hi all,
Sorry to hear of your loss.

Currently, I only have the test for ammonia and I have .25 in the tank. I dose every day with Prime.

If you add "Prime" you will always get an ammonia reading on the test kit, but this doesn't mean you have any free ammonia, there is an explanation here: (http://www.seachem.com/support/forums/f ... a-readings).

...... but this comment about ammonia is confusing to me. Are you using Prime to bring down the ammonia level in the tank? Is this alongside of or instead of filtration and water changes? I use Prime (or similar water conditioners) only on new water that I am adding to the tank to dechlorinate it. Prime seems to have a de-ammonifier in it as well because dechlorinating water treated with chloramine actually generates ammonia, and so Prime also treats the ammonia.

It is annoying that Seachem won't actually tell you how "Prime" works. There is a patent for "Amquel" (EP patent EP 0 278 515 (B1)) and that suggests that "Prime" probably also contains sodium hydroxymethanesulfonate (or similar). The proposed mechanism is that:
"the hydroxymethane - end of the molecule reacts with ammonia to form a non-toxic, stable water-soluble compound "aminomethanesulfonate". The sulfonate end of the molecule reacts with both free-available chlorine, and combined-available chlorine in chloramines. Any ammonia (from the break down of the chloramine) is then mopped up by the sodium hydroxymethanesulfonate".

However there is another patent (Tetra Gmbh US 20080089955 A1 (https://www.google.com/patents/US20080089955)) that suggests that the proposed mechanism for "Amquel" (and presumably "Prime") doesn't work in that matter, but that addition of "sodium hydrogen sulfite to an aliphatic aldehyde" produces a compound (2 Na+[O3S(HO)CHCH(OH)SO3]) which offers protection to fish from free ammonia, again the patent says they don't know the exact reason why it works.

I'm not an organic chemist, but possibly some-one who is may be able to tease the truth out of all of this.

cheers Darrel

[EdWalker]

Apologies for the slow reply. To clarify, I have always put Prime in my tanks as a precaution. I've been running both of these tanks for about a year now, a 55 and a 40 gallon along with a 10 gallon quarantine tank. When my little albino cory got sick the other day I tested the water and found that it had .25 ammonia. I did a water change then. I've been under the impression that Prime makes low levels of ammonia, for lack of a better term, safe?

Anyway, after he died I had another cory show up sick. He had a pus/snot like thing on his dorsal fin. I immediately put him in the quarantine tank and, unfortunately, within 8 hours he had passed as well. Since then, none of the other fish have shown any sickness.

..all of a sudden this hobby isnt as much fun though. I hate losing any fish.

[dw1305]

Hi all,

...... I've been under the impression that Prime makes low levels of ammonia, for lack of a better term, safe?....

It should do.

Do you have a picture of the tank? and a description of the filter? It will give us a bit more idea of what may have gone wrong.

I know they don't appeal to every-one but plants (and particularly floating ones) are very good at reducing ammonia (and all other forms of fixed nitrogen).

cheers Darrel

[Lycosid]

My concern with the Prime is largely that this isn't at all the way I control ammonia, and so I don't know if it actually works. Maybe it does. I try to control ammonia with mature filter media and live plants and I feel confident giving advice about that, but I have no idea whether adding an ammonia treatment every day has side effects or not.

However, let's assume that this isn't the issue, and that your ammonia test kit is actually giving false positives off the breakdown products produced by Prime. Here are some more questions that might help us narrow in on an answer.

1) How old are the cories that died? Are they different in this regard than the unaffected cories? (Older cories might fall ill from something a younger, healthier fish could shake off.)

2) How many cories are together? 40 and 55 gallons sounds great, unless you're running 400 fish, or so few that the cories are stressed.

3) Do you have more than one cory variety in the same tank? I notice that both fish that died are albinos, so probably albino

Corydoras aeneus

. If something hit, say, only the albino fish that might be helpful in figuring out the cause. (Are other fish species in the tank?)

4) What temperature is the tank at?

5) The first cory to die you describe as "turning pink" at the back end. Would you describe this as more like subcutaneous bleeding or more like being skinned? Or something else, like being taken over by a pink bacterial mat?

6) The snotlike glob on the second cory that died is described as "on the dorsal fin". Was it on the fin proper or at the fin base? I'm trying to figure out whether it was an infection that hit an extremity and worked its way in, or an infection that burst out.

One big question here is whether both fish died of the same thing. Did you have a bad disease outbreak, or did you have something go wrong in the tank that stressed the fish and caused two to develop lethal infections from something that is always in your tank but normally not problematic? (This latter possibility is the equivalent of what happens to AIDS patients: after their immune systems collapse common bacteria and fungus can suddenly become lethal.)

I agree with dw1305 that some more basic info about the tank/care conditions would be useful.