I agree with Moray, but I guess if you were bound and determined, and you had lots of hidey places, you can risk a few Ghost Shrimp. They're fiesty, translucent (mostly), and generally speaking, inexpensive. They'll eat almost anything, and are especially helpful if you have a tendancy to overfeed your fish. Mine live the life of kings on a diet of algae, discarded betta bites, and frozen bloodworms.