I was going to put him down and then take him back. I've tested the pet stores water, if I take him back the way he is, he'll just die there anyway, but slowly. And I've treated many a sick fish, I just can't see anything wrong with him besides laying on the bottom. I can't treat if I can't see what the problem is, I mean I figured this would happen. All of his tankmates at the lfs died except one. How do I know this? Because when I was buying him, the girl said "I don't know why these guys keep dyin. These two are all that's left."