URGENT Cories dying off one by one

[kerouac]

I have a ten gal, fully cycled tank. 6 albino corydoras (used to) inhabit it. All params are normal. It is moderately planted with sand, and the plants are doing well. Temp's fine. Now what is happening to my fish?

Three days ago, I noticed one of my albino cories was super pale...he had barely any colour left in him. Like, you could only see a small amount of pink. It was almost as if he had been drained of blood (figuratively of course). No signs of disease or parasites, no injury. Just really lethargic. Well, I did a 50% wc. He ended up dying the next morning anyway.

Now another cory is exhibiting the exact same symptoms. What do I do?? I hesitated to dose with Pimafix with the first fish because the others seemed healthy and I didn't want to medicate them as well...but now it seems that it's something contagious.

Please help. I don't have a quarantine tank. Yes I know, stupid. Anyway, should I dose the meds? They're all I have at the moment. What is killing my fish???

[Lab_Rat]

It would help if you post your parameters, even though you say they're normal. Did you forget to add dechlorinator? Has the temperature of the tank fluctuated? Or the pH? Are you noticing any red streaks on the fins? Are the barbels intact and healthy looking?

Pimafix is used for fungal infections. If you see no signs of fungus I would not dose this. I might dose Melafix, but even with that I'm not going to recommend that until you are able to provide more information about the water parameters.

[kerouac]

Thank you for responding so quickly.

I just finished another test... I've noticed my nitrites are at .5, while they were fine this morning. Perhaps the earlier wc brought them down. Ammonia is at 0, chlorine is 0, PH normal, water is soft.

But yes, the trites are an issue. While I quickly go do another wc...do you have any idea what could have caused this? I feed extremely small amounts and skip feeding once a week. I do alternate between Wardley's shrimp pellets and I've just read that they are not so good, could it be some is rotting in there, despite the small amount? I also had some anachris from Petsmart but the stuff was incredibly unhealthy...I only really noticed when I took it out of the bag. I thought I could save it but it died and left crap all over the bottom of the tank, which I thought I'd done a thorough job of cleaning out.

Could it be I missed some?

Would trite poisoning cause the paleness and lethargy?

This sucks so bad...

[jaysee]

Good job getting a school of corys, as opposed to one or two, but unfortunately a 10 is a bit small (especially if it's got lots of decor/plants) for 6 albinos to live in long term. 6 dwarf corys would fit a lot better.

As for what's killing your fish - how long have you had them?

[Lab_Rat]

Decaying food and plants could cause a minicycle, which could have caused your problem. The wardleys do have a lot of filler, I don't like to feed it. Mine like the hikari bottom feeder wafers. I would keep doing water changes daily until you figure out what's going on. Is your filter running well, no problems with it?

[Scrup]

Did you clean off the dying anacharis? rotting plants themselves wont kill your fish, but the ammonia/nitrites released will, so that would be the indicator in that case.

What do you use for filtration/heating?

cories are known to get into akward places, sometimes to their own demise.

[kerouac]

Thanks everybody.

I just did another 50% wc + gravel vac. I figure I'll keep up with wc's until things settle down, as suggested. They normally get a 50% wc once a week, and I vac once a month on average, more often when I was cleaning out those dead plants.

Everyone else looks healthy. Good barbels. No fin clamping.

The tank is not crowded at all. They have quite a bit of swimming room. I was made aware that bronzes might be too crowded in a 10, so I had planned on moving them to my 40 when I eventually get it up. For the moment they use every corner of this thing and most of them are quite little still. I have had all of them for around 4 months, no issues...a little after I joined this site. The cycle was fishless and took a few months to complete itself.

I am running an AC 50. Cleaned quite recently actually, and is working smoothly as far as I can tell. The heater is a standard Petco brand used for 10 gals.

And I am DEFINITELY changing the pellets to a better quality. They get hikar sinking wafers as well, on alternate days of course. Bloodworms as an occasional treat.

The temp has stayed at a constant 75, no other fluctuations in PH or anything. I am now convinced I missed some rotting veg matter and it has now polluted my tank. Nice going, me.

And the next to fall ill is my biggest and would take bloodworms by hand. ):

Do you think my fish could possibly pull through? Anything else I can do?

[Lab_Rat]

Sounds like you're doing all you can for them. Good luck, I hope they all pull through and it was just a freak thing.

[jaysee]

Hmmm......This is a tough one. May be something inherently wrong that you cannot control? Albinos don't always have the strongest genetics. It's not always the keeper that kills their fish.

[Scrup]

in the future make sure you either sanitize or QT plants, I can relate on the rotting matter...lost close to 6 fish overnight from something similar, if only I had looked behind the HOB intake...dont beat yourself up, these things happen..

hopefully they all make it...

you didnt rinse the filter media by chance?

[Deleted User]

Are you using salt? I think Corys have a low tolerance for aquarium salt (just in case this could be the answer).

[bigdadm]

I have had this problem before, and it turned out that I did not have enough hiding spots for my corys. I had about 12 melanistus(?) cories in a 55 gal with a large oto and a rainbow shark. They stayed uneasy all the time darting all over the tank because the oto and shark took both the hiding spots. Then one after the other started dying until I had 7 left. After I studied them for several hours straight I put more caves in and I haven't had one die since. I hope this helps, it is an alternative if your parameters are fine.