when did you get him?, what are your water peramiters? nitrate,ph,Ammonia,nitrite, SG,
when i first got mine, i had to get a squer and put a shrimp in the end and wiggle it to trigger his hunting reflex. i allways keep my nitates under 10 ppm by water changes and lava rock(fresh from oregon cascades= no iron) and for the bio filter, so i never gat any ammonia readings or nitrite. i use crushed coral and graval with marine salt mix. the indicator of water quality and mood is the belly of the GSP day time its white and night after he eats he gets dark to hide. now i will just drop snails, shrimp, crickets, and frozen silver sides. o ya do you feed him snails i have a 10 G tank just for breeding pesky snails, i went to pestmart and ask for a bunch of there snails and now i have so many in the breeder tank, i over feed them with algea wafers and they took off. i feed him snails about 2x a week to keep his beak trimed down. do you feed yor puffer snails? the other thing is did you get your puffer from wallmart? if so they dont know how to take care of them and are full of parisites. i orderd mine online, and placed it in a SG.005 from fresh water hoping to kill parisites that could be in them, because a nother reason for perisites are all GSPs are wild harvested from the wild. so you just need to trouble shoot all these things and he should be ok. hope this helps