Join Date: Jun 2010
Location: Northern Virginia
Honestly, you'd have the least amount of trouble with a nerite snail and possibly a school of pygmy cories. Since pygmy cories are so small, you'll be able to easily fit a whole school of 6-8 individuals. Plus they're super cute.
Platies, guppies, and mollies I don't really agree with since they can be both aggressive to the betta and illicit aggression from the betta, besides, all prefer harder water conditions, and bettas are a soft water fish. And I don't know, the idea of an out of control colony of livebearers in a tank as small as ten gallons kind of frightens me, lol.
I don't really recommend otos for newly established tanks. All otos you find in pet stores are wild-caught--this means that they are extra sensitive and very unwilling to accept prepared fish food. Many eat exclusively algae, and of all the algae out there, they only eat a few specific kinds. If you have a new tank, you don't have a supply of algae readily available to feed these guys.. so they will starve to death. Many are near the point of starvation already since there is not ample algae in the pet store.