You don't reall need bottom feeders, but they can make a nice addition to your tank. Corydoras catfish might be a good chioce. they are peacfull so they do well with many other types of fish. they do best in groups of six plus, but four is o.k. they should also be kept in groups of thier own spieceis. There are many different spieceis of cories. They eat peaces of left over fish food, algie pellets, mine also like sinking frog food. They are not considered algie eaters. They are fun to watch, they love to play. Mine like to swim back and fourth through the current my filter makes. I hope this helps.