Corydoras breathing rapidly all the times

[Karen B.]

I have a community tank.

Population : 1 honey gourami, 10 chili rasbora, 7 false julii cory, 5 otocinclus and 4 nerita snails.

 

Cycled, planted, temp about 75, Ph 6.6

Kh 1 (drop) / 0(aquarium test strip)

Gh 9 / 300

0/0/10

WC + gravel siphon every week or 2 weeks depending.

 

one of my corydoras is always breathing rapidly. And rarely hangs with the others. He mostly stays still and breath rapidly. No one bullies him, except sometimes other cory bumps into him. I rarely see him eating and I find his color turning a bit yellow? His barbel are also damaged (shorter) then my other coryd.

 

I know my ph is a bit low and so is my kh, I bought Seachem alkaline buffer to correct that. I have a sponge filter. None of my other fish have his behavior- in fact my other cory breed like rabbits.

 

Any idea of what it could be?

 

[DaveO]

It sounds like this one cory is stressed. It is not the other fish bothering him so I would look to water. It looks like your tank is very clean, too clean perhaps. Personally I would stop vacuuming the substrate. Corys love to sift through it constantly looking for stuff to eat. Also I would stop trying to alter the ph/kh with that buffer. Instead incorporate some crushed coral in a hang on back or mesh bag hidden in the tank. Try to add food specifically for that cory. 

[Mmiller2001]

Your pH, GH and KH are near perfect. Don't change them. Have you, at anytime, treated for parasites?

Could be a bacterial issue as well.

There's no such thing as too clean of water 

Are they new fish?

Edited August 14, 2021 by Mmiller2001