Buy frozen raw shrimp when its on sale. I usually get it for about 6$ a lb. Buy clams and freeze them for 48 hrs and then thaw out and toss in the tank. This will keep there teeth in check, they love biting the shell. Get some vitamins, Selcon. After you thaw the frozen shrimp out, remove the shell. I poke the shrimp and then put Selcon on it , let sit for 20 minutes, then cut up and give to the puffer. Use a stainless fork so when he bites, he doesn't destroy the feeding tool. GL