GSP and snails.

They will naturally eat snails and that's a fair part of their diet so feeding them snails will never hurt. I say feed them whenever you feel is neccessary. I always prefer floating pellets but that's just me

For my figure 8 puffers I feed them snails once a week. [One or two for each] Other than that I feed them tilapia or brine shrimp once a day. I try to feed mine pellets but they don't eat them. When I will not be able to feed them for 3 or more days I put live brine shrimp in the tank.

I would feed a majority of snails, if possible. I've heard GSPs, SA and F8 puffers have very quick growing teeth. Their teeth will become overgrown if they don't get enough crunchy stuff and then you'll have to perform dental surgery, or they'll starve to death from not being able to open their mouth wide enough. I feed my Mbu puffer 80% of his diet of closed mussels, injected with vitamins.

I agree with Psylant. I have 2 GSPs that are starting getting pretty big. Snails are a huge part of their diet- multiple times a week. I have a 30 gal tank in the basement (though 5 or 10 gal would work too) for breeding snails exclusively. I try to have about 100-200 + on hand at a time to keep up. Mine will not touch pellets unfortunately. They eat bloodworms, snails, occasionally brine shrimp, but enjoy the hunt or larger things- then get a big treat once a week like a few ghost shrimp, a live crab, frozen crayfish, a feeder guppy, etc. their hands down favorite is live crab. Amazing team work taking it down. Eyes first, then get the big claw, then flip it over and take turns devouring it.