are a variety of different species out there, all fairly well suited to
being with puffers. Most mollies are semi-aggressive, and will dish
out just as much grief as they get. Avoid the ornate ones, such as
the lyretails, since they may be too tempting to turn down as a fin-snack.
They can be adapted to brackish conditions as well.
Barbs- Barbs are great partners for puffers, since they are also aggressive, and fast swimmers. They come in a variety of colors. I have had great success with tiger barbs. They also acclimate to brackish conditions. Since they are schooling fish, it's best to have at least 3 at a time.
Plecos- You'd think these fish would make easy marks for puffers, but for some reason I've never had any of mine attacked. These catfish are good for cleaning up your puffer's mess as well. The only advice I have with these tankmates is to watch which species you get, as they can get quite large. Some plecos can handle brackish water. I have one in each of my tanks.
Mollies- see above.
Plecos- see above.
Bumblebee gobies- Here are some cool little fish. They are yellow and black banded, and for some reason puffers don't normally eat them. They are scaless like the puffers, and have a suction-like fin on their bellies which enables them to hold onto things like the side of your tank. They are small, but fast. Most of the time they are too fast for puffs. They'll hide in small areas when threatened.
Scats- Scats make good partners because of the way they actually eat the detritus and some waste in the tank. With puffers being as messy as they are, it's not a bad idea to have some of these guys around. I have a couple of silvers in the tank with my green puffers, and they never bother them. If you've seen what these fish eat, I don't blame my puffs! They are still attractive fish, especially the silver scats. The spotted scats have similar markings to the green and spotted puffers!
Cichlids- Some cichlids make good partners as well. They are fast fish from the African rift lakes, and handle alkaline water quite well--they actually thrive in it. They come in many bright colors, and can accent a tank rather well. Cichlids are a little nippy themselves, so they are a nice match for ornery puffers.
If you have some tank partners for your puffs, I'd love to hear about them...send me an email.