I have a community tank that's between 10-20 gallons (Not quite sure but it's got a least some space for two or three more fish. I currently have one female betta and five white cloud minnows. I was wondering what else I could put into the tank without disturbing the current balance. I just added two of the minnows and the female betta so I will be waiting at least a week if not more before adding anymore. But I want to do research first. What would be good tank mates for them? Obviously I can't get anything that gets much bigger then 2 "and even that is pushing it. But guppies are out of the question because the betta might attack them.

Since you have betta in your tank and you're not sure what tank you have, you're really limited on what you can add. Probably cherry or ghost shrimp will be your best bet. Measure you tank dimensions and calculate it here: http://animal-world.com/encyclo/informat ... pets question and answers,www.5d2d.com

Edited:

You can add some Otos but none of the bottom feeders like corydoras. They need at least a group of 5 and they grow for about 3 "

WCMM are coldwater fish. Not even compatible with a tropical Betta.

If you have a female betta , you'd be best off getting 4-5 more if it's a ten gallon or more tank.

With both the betta (and the minnows if you keep them), they love densely planted tanks. I'd actually look at adding some live plants. Ranging from carpet length, to ones that break the surface of the water.

I'd remove the minnows.

ottocinclus sucker catfish are cute and inoffensive and they don't get much bigger than an inch

my love for fish