Metal filter tube are great for aquarium fish tank, to promote gas exchange and increase dissolved oxygen levels. Great for tropical fish farms, koi ponds, waste water systems, cooling towers, and other commercial and industrial systems.For use with wet/dry filters (here is not included). An attractive way to make your aquarium shrimp fish safe.Tiny animals like most freshwater shrimp, invertebrates, as well as small fish and fry are at risk of being sucked into the large slots on most standard intake strainers. When cleaning is required, simply brush any accumulated debris off of the filter guard with your hand or a soft brush of some sort like a tooth brush. 1x Filter Guard.