Ok, so i pretty much gave up on the "shells" mainly because i couldn't figure out what they're called in English.
I picked up some brackish snails (black shell, forget the name but it had something to do with "stones" or "rock"...) who i'm hoping to breed, as well as some marine hermit crabs. The guy at this pet shop actually knew his stuff! I was happily amazed. He mentioned that puffers like to bite coral, and that's a good way to keep their beaks trim, and also the hermit crab's shells are also good for beak trimming.
Only thing is that my F8 was meant to eat the hermit crabs, but so far he's leaving them alone (as far as i could tell). He was definitely interested in them, but they spend most of their time hiding from the puffer, so either he can't find them, or he doesn't like hermit crab.
On the plus side, these hermits are eating the leftover food that falls to the bottom of the tank thus cleaning after the puffer! Awesome!
