They are not super active but have you ever considered a lurker type puffer? Maybe a Congo, arrowhead or hairy puffer would work. They sit and wait in ambush for their prey but will recognize you and come out. I use feeding tongs on my hairy puffer to feed krill and will put in earthworms and shrimp and he will devour them in a way that you have to respect them, lol. Great little fish!
