believe it or not, I found one of these puffers for 12.99 and it was a great size, but I have heard so many horror stories about them not eating, always being stressed out and ect....so I checked to see what type of conditions this fish has been in, and what I did was matched the temperature of my heater to what this fish was in, and now he eats, he swims, he plays, he is great....the temp is 84, i think they love the warmer water....I would suggest trying to raise your temps......it shouldnt hurt anything ...