My daughter won a betta and I've got him set up in one of those 10G tank kits from wallyworld. I'm thinking she'll end up wanting to get him a "friend" so I'm curious what might work. I've only ever kept them solo; well, once I tried a pair but she murdered him. Anyway I thought it might be tricky...little tiny fish are in danger, and bigger things might nip the betta. Maybe cories? How many cories could work in a 10G with a single betta?