With your comm, the only species I can offer would be Colomesus asellus. They're a true FW species and not as likely to tear tankmates up as would other FW species. These max out at about 5".
if the balas will get to a foot and the barbs to about 8 and the gourami to 4 is that the only puffer? My water has a bit of salt if that helps make my field larger? Tak you for your help again
You should not be using ANY salt with FW fish. I do not suggest puffers at all, in a community tank. Your tank is already fully stocked. Your "shark" & barbs are schooling fish.
No its not marine salt. In my water there is about .05% of salt in it. I wouldn't put marine salt in there. Thank for your help and will strongly consider it!