Need help with Corydoras acting weird!!!

[hroom88]

Around 30-40 mins I think is ideal. But if the carry bag is a small one, then I'd suggest smaller amounts of water(> 1 cup). If you have the patience to conduct the acclimatization for 2 hours, no harm done. In fact then your fish wouldn't feel a thing. This is good when acclimating expensive fish. I'm sure you would want to do anything to ensure your fish to survive, that you paid top $ for.

 

[hroom88]

I recently bought 6 Corydoras for my tank (85 gallon). I acclimated them properly and slowly. Even checked the pH, ammonia, nitrite, and nitrate levels to make sure they're ok. I released them in the tank after acclimatization, all of them were fine. Then I went out for a couple of hours. When I got back I saw five of them were fine and so were other fishes in tank (platys, swordtails, and zebra danios).

One of them got stuck in the plants and was upside down. My first thought that it was dead, but then I looked closer. The gill is still moving so it is still breathing. I helped him getting unstuck from the plants but then it swam funny and upside down. Like it had so much trouble with buoyancy. It continues to swim upside down (struggling mind you), if it stops swimming it'll just sink right to the bottom.

I don't know what's going on. The other fishes are just fine. Can anybody help me out?

Thanks.

PS. Can someone help me ID what type of Corydoras these are? I'm thinking Julii or Delphax, but I'm not too sure.

looks like NH3 burns

 

[yudhas]

looks like NH3 burns

Yeah. It looks like they were kept in a tank with NH3 present. That one ended up dead and I got a replacement. But now another Corys is sick. Not sure what it is, but I'm guessing is a fungal infection. Unfortunately I don't have any medicine except Paraguard and Cupramine. So I've moved it to a hospital tank and been using Paraguard to treat it.

My other Corys and other fishes are doing excellent in my main tank. I checked my parameter this morning and they are:

NH3 = 0
NO2 = 0
NO3 = 10
pH = 7.4

I have a total of 6 corys and I'm running two filters on my tank, the water is excellent. So I don't know what cause the other one to be sick.