Red Sea Fish Pharm ARE50180 Prizm Hang-On Skimmer with Pump for Aquarium Prism skimmer remove proteins before they break down and pollute the water The prism skimmer enhances the quality of the aquariums environment as well as its appearance Suitable for all marine and reef aquariums up to 100-gallon Includes external water pump Ideal for both new and experienced marine aquarists