Well right now in my 10, I tried setting up a Betta/Cory/Paradise fish tank...it didn't work, so I moved my bettas into their bowls :sad , and kept the Paradise fish in with the corys. I am not liking the paradise fish much -they attack even ones of their own species.. not cool-, so I am thinking on moving the corys and bettas into a bigger tank, and leaving the paradise fish in the 10 by themselves. I wasn't thinking about HUGE catfish, just ones that are around the 4''-14'' area, and not big enough to swallow a betta. A little off topic, are livebearers good with bettas¿ A friend of mine has a musquito fish that breeds like a rat, and I was wondering if one would make a good betta companion.