I used to have 2, both in small tanks(2.5 & 5.5 gallon). I returned one because I wanted to have shrimp in the tank. They are not intentionally destructive, but I've had one pull up some Rotala sp. mini in an over-zealous pursuit of snails. Other than that, not a stem or branch disturbed in either tank. they are great fish, especially for a planted tank. As for tankmates, check out this thread. I had otos with both puffers with no problems.
The only time I've ever had problems with dwarf puffers and their tankmates was when I purchased already mature fish. I buy them as young as possible so they learn to coexist with other species(other than shrimplets and snails) and it's worked 100% for me.
IDK about DPs, but many people feed frozen, fresh and freeze dried shrimp & krill in addition to pond & ramshorn snails.
Anything meaty that they can keep their beaks trimmed on is good. They're messy - plan for that (good mechanical filtration & flow, frequent water changes or at least pad cleanings depending on filter type).
Squawk - DP's do not need to trim their beaks like normal Puffers would need to. A normal puffer does this on the hard shell of a Snail. A DP will suck the snail out by grabbing onto the foot and sucking.
I do highly recommend frozen blood worms. I would thaw half a cube, pinch it between my fingers, and hold it just under the surface with the blood worms dangling. My DP would eat right from my fingers. And with this feeding method my puffer warmed up to me, and was always a beautiful color.
I feed my four dwarf puffers live black worms. They love them and go crazy. They know that they get fed after work and will start pacing the glass like crazy about an hour before hand. My tank is fairly heavily planted with stems and a lot of time they will stay in the bottom on leaves or behind rocks. Mine are overfed because my girlfriend well.... she overfeeds them. If you go with live black worms be sure to get a black worm keeper. We buy a whole portion and they last 2 months and with the keeper they don't die, just have to keep them in the fridge.
chago - Your DP should do it's own thing on a regular basis, but it also should be at the glass so "greet you" when you come back to the tank. DP's are very personable fish. If your DP Is always on the bottom and never moving, or getting real excited you may have a sick fish. Your DP should act at least as Ravenous's DP did when feeding, also it should do that almost every time u go to the tank. (that is once you start to be "reconized" by the dp)
Ok so I pulled a realy bone head move. What I thought was a dwarf puffer was a green spotted puffer, totally different fish. I got him back to the store and back to heath before any thing happened. And now I go on the hunt for a true dwarf puffer, I fell so bad for putting the fish though that. ](*,)