One of my four green corys is laying on his back on the bottom breathing very rapidly. He is sorta bloated, but was for the past couple days but acted fine until tonight. All the other fish including the other corys are all acting normal. I don't know how long this cory has been doing this as I just got home and happened to see him like that behind the driftwood. I've had these corys for about two months now with no problems and no previous deaths. What do you think it is? What should I do about him now?
tested two weeks ago:
p.h 7.1
ammo 0
nitrite 0
nitrate 5
tested two weeks ago:
p.h 7.1
ammo 0
nitrite 0
nitrate 5