I use guppies in all my tanks. Best pest control ive used so far .Baby guppies love these things. I once had an out break and threw in a few baby guppies....all seed shrimp were gone in a weekend. For some reason they never came back even after I took out the guppies.
I started a thread here a while ago with pics of the whole process. Search for it and you'll see how clean my tank looked after the guppies went to town.