I just got 3 adfs from my lfs last night. Two seem to be doing fine, but I noticed that one never came up to the top of the tank. I left him alone, thinking maybe he just needed a little time to chill out, but this morning he was at the bottom of the tank belly up! I figured I had lost him in the night but when i picked him up he moved around in my hand and put his head up as though gasping for air. I have him propped up in a bit of net so that he is closer to the surface with a bit of hikari cracker. Is there anything I can do? Or should I just let him go...