You can try feeding a variety of raw meaty foods including Shrimp, Scallops, Crab, Krill, Mussels, Clams, Prawns and many more..... You can also try feeding some greens, Nori, Fresh frozen Peas and broccoli thawed.
If you use a nori clip it may bit at that, my trigger rips them apart every time, watch any cords or Powerheads (use a guard) that are in the tank, Puffers like to chew.
Kaye