Hey therere when u say Puffy what sort of puffy do you mean? a dwarf puffer or an acutal puffer fish?
I have a dwarf puffer fish but i added my betta after my puffer fish had hit puberty (aprrently all DP's hit puberty :S and this is when they can get very agressive, and bitey.)
I only havea 30 litre tank mand my beta and puffer fish arent fighting at all, everything is ship shape x
Puffers are best solitary. Unless its a really big tank with lots of plants. They will get aggressive and attack other fish. Only be a matter of time before it goes after your betta,then no more betta. Best to give a puffer its own tank and a betta its own as well. Its iffy with bettas and tankmates,some may be okay with it,some not.
i cant affford to upgrade just yet, im looking at getting my Bf a tank though, found dads old heater but i know my bf would prefer the fightingg fish, hadnds down hes that kinda bloke... but i was planning to go with him to pick out his own x