There are quite a few true freshwater puffs! It's much harder to find a true brackish puff. Figure-8s are the only ones that do well in brackish for their full lifetime, as long as you use a marine salt mix (not rock salt or sea salt). GSPs and Ceylons need increasing salinity (again, use a marine mix) until they reach adulthood, at which point they should be in full marine.
Freshwater puffers, including dwarfs, SHOULD NOT have marine salt added. Dwarf puffs are river fish who need very clean 6.5-7.2 pH water. Salt will only hurt unless you are trying to get rid of ich or some similar problem. Many people add salt because it is just one of those things that has become a panacea. Salt is useful only in certain very specific circumstances. The rest of the time, your best friend is the weekly 50% water change. Really 50%. Puffers are dirty and very sensitive to their own byproducts, so you gotta keep 'em clean and test that water every week and the instant you see a problem.
True freshwater puffs:
Auriglobus modestus (bronze puffer)
Auriglobus silus (golden puffer)
Carinotetraodon irrubesco (redeye)
Carinotetraodon lorteti (redeye)
Carinotetraodon salivator (redeye)
Carinotetraodon travancoricus (dwarf puffer)
Monotrete abei (Abei Puffer)
Monotrete baileyi (hairy puffer)
Monotrete Cambodgiensis
Monotrete Cochinchinensis (Fang's puffer)
Monotrete Palembangensis (Palembang Puffer)
Monotrete suvattii (Arrowhead Puffer)
Monotrete Turgidus (Brown Puffer)
Tetraodon cutcutia (Common Puffer)
Tetraodon duboisi (Dubois' Freshwater Puffer)
Tetraodon lineatus (Fahaka puffer)
Tetraodon mbu (Mbu Puffer--say "ehm-boo")
Tetraodon miurus (Congo Puffer)
Tetraodon pustulatus (Cross River Puffer)
Brackish:
Colomesus psittacus (Banded Puffer, high-end brackish to marine)
Tetraodon biocellatus (Figure-8, low-end brackish)
Tetraodon erythrotaenia (Red-striped Toadfish, very low brackish or alkaline fresh)
Tetraodon fluviatilis (Ceylon Puffer, high-end brackish to full marine)
Tetraodon nigroviridis (Green Spotted Puffer, high-end brackish to full marine)
Tetraodon sabahensis (Giant Spotted Puffer, variable salinity alkaline water)
The full marine puffers are too numerous to list. Read all about these and other puffs at the PufferPedia,
The Puffer Forum • The PufferPedia
I have personally kept
Tetraodon nigroviridis, Tetraodon biocellatus, Carinotetraodon irrubesco, and
Carinotetraodon travancoricus, as well as a marine Spotted Sharpnose,
Canthigaster solandri. They really are the coolest fish ever, and very smart too. My GSP used to do tricks.
