Cory cats dying?!

[Tropical]

Today I went to do a pwc and one of my cory cats was dead and stuck to the filter. About 20 minutes after removing the dead cory cat and doing the pwc, I went back to the tank. One of my other corys was having trouble swimming. He was floating all around the tank and trying to swim, but all he was really doing was flipping in circles. I turned off the filter for a few minutes just so the current wouldn't keep pushing him around.

I don't see any physical signs, no open sores or anything. The water is 0 ammonia, 0 nitrites, about 20 nitrates. Any ideas about the cause and treatment options?

 

[gabysapha]

Size of tank? Stocking?

Did you treat the water for chlorine? Did you introduce copper or meds?

Im sorry about your cories i feel particularly bad when they dont do well. They seem so innocent yknow?

 

[Tropical]

20 gallon long tank, with 3 cory cats (started with 5) and 5 neon tetras. Treated for chlorine, no copper, possibly some traces of MelaFix.

 

[absolutangel04]

Did you use melafix recently to treat anything? Or have you used anything else to treat any conditions?

 

[Tropical]

I used the melafix about three weeks ago before I got the corys to treat a neon tetra with a nipped tail.

I haven't used anything else since then. I've been feeding Omega One flakes.

 

[Reygan2]

Are your neons showing any other signs? Check them closely, it can be hard to spot anything on them.

How long have you had the cories?

 

[Tropical]

I've had the corys about 2 weeks. I got five, one died after 24 hours.

The neons look fine, colorful and active.

 

[absolutangel04]

OK, well, sicne they died after 2 weeks and all your parameters are good, IMO it is quite likely that you just got bad stock. Sometimes corys can be pretty sensitive to meds, but if you used it weeks before you purchased the corys I wouldn't be concerned about it. Bad stock and result in spontaneous fish death even about a month or more after purchase. Its a bit hard on the fish to be shipped, so any underlying issues can manifest themselves, but sometimes it takes awhile. JMO.