25 Gallon, you would probably be looking at anything from Fig8's (Brackish), SAPs, Dwarf Puffers, Carinotetraodon's, and some of the smaller Tetraodon species.
Saps are shoaling Puffers, but they imo would be a pain in the arse to deal with...constant teeth growing and dental work. My fave quote from someone on the Puffer Forum was "i swear if i sit and watch my SAP's i can actually see the teeth growing infront of me"
Most Puffers dont get on well with anything else, although there are exceptions.
Your best bet is to look in your local shops, see whats available then research their requirements.
