I'm pretty sure it depends on the tempermant of your fish what he will be able to live with. In a 10 gallon, I would just recommend having fun planting the tank and making lots of cool hiding places for your betta instead of worrying about tank mates. My betta is in a 29 gallon community tank that he does well in with the other fish, but this is because of the extra space he has. If you really wanted tank mates you could try out ghost shrimp.. except that brings up some more problems as your betta could decide he wants to attack them (mine doesn't but it's all about the individual). I also had a problem where the pet store sold me the wrong kind of shrimp and I had to take everything out of my tank to catch the false ghost shrimp before they attacked my fish. If you would ever think about upgrading to a bigger tank, ive had good luck with my Cory cats, rummy nose tetras, and rubberlip pleco