Small tank breeders

[OohFeeshy]

I'm hoping to get a 7g tank (or maybe 10g, but lets stick with 7g) for spawning bettas at a later date. Anyhoo, I hate to see empty tanks Pretty much, anything interesting thats not a betta or livebearers. Or something I can breed in there (again, part from livebearers and preferably not cories). Thankeee