Bubba643
Aquarium Advice Freak
Figured I'd post a pic of my juvenile 2.5 inch Royal pleco to illustrate the effects plecostomus can have on the bio load of a tank. Important to note this particular fish will grow to 15-17 inches as a mature adult. Pictured waste was a result of feeding one dime size algae wafer and I also have a large piece of driftwood he snacks on with little to no free growing algae in this tank. This is about 24 hours worth of waste or less.
Most inexperienced people purchase pleco's thinking of them as a built-in cleaner of the tank. While they do clean the interior algae some what, there overall effect on the tank can be quite the opposite of clean, especially in under sized or under filtered aquariums. I happen to love them and think they are fascinating to watch and take care of. However, they need a lot of space, filtration, and water maintenance to thrive.