The Puffer Forum

I am worried about my porcupine puffer. He has always been eager to eat and would eat of of my hands, but now, even though he seems excited to eat, when he tries to grab the food he can't. He opens his mouth and jumps at the food and always comes up short. I tried holding it against his mouth as he tried to bite it and I don't understands why he can't eat. He can open his mouth and seems otherwise healthy.
He is a 5" in a 55 gallon tank. The levels are all okay, except nitrates are high and I am taking care of them with water changes and carbon. I have added vitamins and tried tempting him to eat with squid. I would love to feed him crunchy food to keep him from getting lock jaw, but currently I can't get him to eat anything. This has gone on for about 5 days now. Do I need to force feed him? If I do that is there hope that he will go back to eating on his own? I love my puffer and want to keep taking good care of him, but I don't know what to do.

What has his diet consisted of? Carbon does not remove nitrates. Only water changes can.

Crunchy foods don't prevent lockjaw, proper nutrition does. What are your exact water stats? Please answer all of the questions at the top of the forum.