• Effective Surface Skimming • Safe for small Shrimps & Fishes • Easy Cleaning • Adjustable Flow Rate • Adaptive to Water Level Changes • Multi-Directional Flow Outlet The aquarium water surface may develop unsightly oil slicks due to fish waste, uneaten feeds and dirty air. Oil slicks reduce the amount of gas exchange at the water surface and the air above, which will reduce the amount of oxygen in the water. Oil slicks also cause reductions in light penetration into the water. The OF Surf Clear Aquatic Surface Skimmer can effectively remove any oil slicks and keep the water surface clean and clear.