Join Date: Sep 2006
Location: Northern Virginia
Dwarf Puffers in the wild Are poisonous, but not venomous. Which mean's you would have to eat them for it to be a problem, and, since the particular algae and bacteria they need to eat to produce the toxin are not present in sufficient amounts in a home aquarium, it's unlikely to be a problem, particularly not with commercially bred specimens.
That said, the standard answer is that dwarf puffers can be kept with Dwarf puffers, and sometimes with ottos. They take up 3 gallons per fish, and no more than one male per 10 gallons. So you could probably pack the tank with 3 males, 12 females, and 5 ottos (10 if you can provide a daily fresh river stone coated in algae.)
I have read in a reliable source (TFH) of a dozen fish being kept handily in a 29 gallon tank. So long as you have no java moss or comparable plants on the substrate, the territoriality that comes with breeding probably won't kick in.
I have read several anecdotes of small numbers of DPs in large community tanks. I'm not going to try it myself, since I fully intend to set up a 20 long with a half dozen females, a couple of males, aquascaped to provide three distinct territories, with clumps of java moss only at the extreme ends of the tank. If I did have a 55 with a couple or three DPs, I'd make sure there were lots of plants. At least 4 good stands of stems in clumps along the back and to the midline, with plenty of rosettes between and some nice, branchy driftwood for obstacles. I'd also put in a fair number of caves and hiding places, and a clump of java moss at one end of the tank, screened from view of the rest of the tank with stems, driftwood, rockwork, and whatever other trick of aquascaping and perspective I could pull short of walling it off. I'd avoid any long finned or slow moving or scaleless fish (with the possible exception of kuhli loaches at stay hidden most of the time anyway), anything big enough to eat the DPs or mean enough to kill them - That basically leaves barbs and danios and rasboaras, More active (but not nippy) tetras, some callicthyid and loricariid catfish, maybe rainbows, and some livebearers. I'd be really careful to not put in there any fish that I thought was too expensive to lose.
Think about that and come back with a mix you like, and we'll see if it's worth a shot.
Logic is only the beginning of wisdom