Bad betta tankmates (due to fin nipping or fights):
Barbs
Rasboras
Danios
Gouramis
Goldfish
Cichlids of any kind
Fast moving, semi-aggressive Tetras (like blind cave tetras)
Good betta tankmates (usually leave betta alone, betta may chase them!):
Cory cats
White Cloud Mountain Minnows
Dwaf Plecos (Candystripe, Clown, any >4" max length)
Iffy betta tankmates (work sometimes under right conditions and fish personallities):
Livebearers
(since they have different water requirements I don't know if it would work, some people have success, others don't. Sometimes a particularly large livebearer, male or female, may become a dominate bully)
Tetras
(some slower moving tetras don't seem to be a problem, but I have had people report that even a school of neons may be tempted to nip at the finnage of a betta)
Rainbow sharks and loaches
(Bettas usually leave bottom dwellers alone, and so long as the betta stays out of their territory, they'll leave it alone as well)
Currently my purple (yes I finally bought a purple one!) male betta is currently residing in an Eclipse System six with three Emerald Green Cory Cats, one Clown Pleco (L103), and one 1" rainbow shark. I did have him in there with a Thicklip Honey Gourami and all he did was chase it around, so I transferred the gourami to my other tank so it wouldn't get harassed. Now the betta is the only thing that "swims" around the tank. The rainbow shark hangs in his crevic, the pleco in its crevic, and the cories kinda just root around the bottom minding their own business. The only thing the betta does is flare at his own reflection occassionally.
~~Colesea
