I bought two firefish yesterday. They both seemed to do very well yesterday, both swimming together and what not. Woke up this mornign and was was fine and hiding. The other one was swimming as if he was drunk. I noticed behind his gills it was red almost like internal bleeding. I had to go to class so I moved him into his own area in the fuge are. I came home and he is now dead. What cuased this death? Was he sick even when I got him? The other is swimming happy as ever right now and my clown has been in the tank for about a week and is very happy also.
I did a quick test on NO2
right before I left. Im showing 0 nitrite and maybe 2-3ppm of nitrate.
Also the bleeding only seem to be on one side of the fish (other side looks fine).