How to tell if a betta is aggressive or docile?

[Pataflafla]

Your male might be able to go into a community tank with some snails and shrimp if he is introduced into the the tank after any snails or shrimp. As far as the cories go, your tank might be too small for them to comfortably live.

I don't know how to tell if your guy will be too aggressive for tank mates until after you've already got some, but if you introduce him after the others are settled in, he won't feel like he has to guard his territory from them (hopefully).

I've got a male veil tail in with 2 male mollies and another male (bought as female, but we're seriously doubting now) veil tail in with 2 female mollies and the fry from one of the mollies. So far only a few of the fry have been eaten (The ones that were failure to thrive so they wouldn't make it anyway). And the veil tail in with the male mollies only occasionally nips their fins, but he likes to be in a community tank (He tail bites if he isn't). Overall, neither are overly aggressive or protective with the mollies.