I am transitioning all my tanks to sand. I have geophagus, nanochromis, woodcats, banjo cats, cory cats, raphaels, portholes and hoplos. All of these do better with sand. As has been stated above detritus tends to stay on the surface rather than disappearing into larger grain gravel. I feed pellets ranging from .5mm - 3mm and sand keeps food from being lost in the gravel too.
