Fish in aquariums depend on a constant flow of water to supply them with food, oxygen, and maintain a consistent water temperature. Aquarium filters were designed to capture any debris in the tank and absorb any chemical wastes that might be in the tank by pumping water through filtration media. The two main types of aquarium pumps are inline and submersible. Inline pumps are part of an external aquarium filter and they are placed outside of the aquarium and connected to the tank with inlet and outlet tubing. Submersible water pumps are placed inside your aquarium and they draw water across a filter so that it can be cleaned, and then force new water into the tank. If you want to have a bigger water flow, you can get an aquarium powerhead that will create a nice underwater current for your fish to enjoy (and help heat the water too).