My girlfriend has a puffer that is not looking so good an were not sure how to help it. He is a green spotted puffer and currerntly lives in a 5 gallon tank. He will be moved to a 60 gallon tank or bigger within a week. He has become very inactive, a bit darker than when she originally got him and has started to refuse beef heart, even though he has eaten it before. I put some ghost shrimp in his tank as snacks and he just ignored them. The water is brackish (1.012), and the temp is around 78-80. Any suggestions as to how to perk this guy up? Currently he is about 3 inches long.