As mentioned before--crunchies are important. Most puffers are not interested in freeze dried foods, flakes or pellets--they want fleshy foods. Raw cocktail shrimp, mussels, cockles, clams, crab legs--they must have the crunchy foods or their beaks overgrow. I've seen a few that will take frozen foods, but they've always done better on fresh foods. Make sure not to overfeed--their digestive system is very slow, and overfeeding can result in rotting foods in their intestine--often lethal.