Thanks for everyonw's replies, but I'm sad to say that both puffers died. We won't be buying any more puffers anytime soon... at leat not until I do alot of research on the little guys.
PLEASE HELP!!!!! My boyfriend bought two fresh water green-spotted puffers 4 days ago and we have them in a new tank with two crabs that are about the same size as the little puffers. Both are skinny-looking but the healthier looking one has been turning black. He'll be his normal colors one minute,...