Aquarium Gentle Shrimp Fry Tank Sponge Filter,  Air Pump Drive,  Manifold Size Recommended tank capacity of 50 gallons use Sponge filters provide both mechanical and biological filtration Provides the ideal location for bacterial colonization Does not trap fish fry. Suitable filter when breeding and spawning Discus, Dwarf cichlids, guppies, and killifish They are useful for as breeding filter or as secondary filter