Is the cory OK?

[nlifs]

Been seeing something strange today ...

After a partial WC yesterday (about 25%), one of the corys started gulping a lot more air than usual. It swims up to the surface, but instead of one gulp, it takes about 3 of them (bobbing up and down by the surface) and then shoots back down to the gravel. Been doing this regularly since the WC. Also seems quite lethargic and doesn't move much along the gravel. Finally, when I try to take a close look when it's resting, it seems to be breathing pretty hard.

Should be plenty of aeration due to airstone and HOB filter.

Relatedly, I found a dead rainbowfish this morning ... not sure if the two are connected.

Is it possible that the WC induced some sort of pH shock? Last I checked, the tank is around 7-7.2, whereas the water out of the tap is higher (7.6-7.8), possibly because of the small driftwood in the tank or general degradation of pH over time?

Other than monitoring, anything I can do for the cory that seems to be in some distress?

Thanks as usual, and best wishes to all on this holiday season!

 

[nlifs]

And now he seems to be shaking a bit on the gravel (in adding to very rapid breathing) ...

I'm guessing that there's not much I can do for him at this point?

 

[Andy Sager]

It doesn't sound good for the Cory. Because it happened right after the water change, it raises the possibility that there was some kind of reaction to something that occurred with the water change. Could be the Ph, could have been the temperature, could have been an accidental injury resulting from when the water was being replaced. Hard to tell. Usually if there is a water difference situation, all the fish would be effected more so than just one.
As for the rainbowfish, as I said before, these species of rainbowfish are short lived ( 2-3 years) so it could very easily be an age related thing. The problem is that you don't know how old your fish are unless you get them from a breeder or you've had them since they were eggs. If the rest of the fish are doing okay or not showing any signs of stress, I would not be concerned.