In my 20 gallon tank, no matter what, even after weekly water changes, there is always detritus built up on and in the substrate. It seems to be plant matter and fish waste. I have 3 otos in my cleaning crew but they dont seem to help the problem. In fact, they poop a lot and sometimes i think add to the mess. They just love the glass and leaves in my tank. That's it. What are some fish or inverts to get for a good cleaning crew? I have an open top so I always try to avoid species that might jump out. Like I'm always afraid shrimp would jump out. Also I have hair algae in my tank so if anything eats that, that is a plus. Otos dont care for it. And if you can tell me species that are easy to find at a lfs, nothing too crazy or rare please.