If you don't mind that they're African, jewel cichlids are probably the meanest you can find at that size. They regularly kicked my JD's butt when he was twice their size! (In addition to all of my other fish of course).
First time I owned one I caught it wild and put it with killies larger than itself. I ended up with 5 tail-less killies, no more snails, and I don't even have to mention the pet ghost shrimp.
First time I owned one I caught it wild and put it with killies larger than itself. I ended up with 5 tail-less killies, no more snails, and I don't even have to mention the pet ghost shrimp.