I just had my first death in ages and I'm just bummed. I got a nice (probable) trio of Gymnogeophagus labiatus, a couple of months ago from a semi local fish store. Fish were doing great, growing well and just starting to color up. Fed this morning, went out for a while, came back and found the biggest, at 4 inches, which was of course the probable male dead. Man, that hurts. Checked all my parameters and everything was fine. No ammonia, no nitrites, nitrates at 10ppm, ph was the same 6.4 it always is, no visible trauma, just a dead fish. Only thing I can think is that possibly he died of stress, because my 4 inch male Chiclasoma (Australoheros?) oblongus has been chasing the labs around some. I know sh*t happens and it's part of the hobby but I can't help but feel bad. I consider myself a pretty good fish keeper but I KNEW it was time to move them out of the 55 with the oblongus, I even had the other tank set up and ready to go and just waited too long. Man, I feel bad.