Most sea sponges are detrivorous, meaning they consume organic debris and various microbes that drift through ocean currents. Harp sponges, however, are carnivorous and use hooks located on their arms to catch shrimp and other small animals.
A sponge eats by drawing water through its pores and filtering organic particles. The water is then ejected back into the surrounding environment. The entire surface of the sponge is able to carry out this process, making it an extremely efficient filter feeder. Coral reefs offer abundant supplies of nutrients, making them ideal habitats for sponges. As simple animals, sponges are collections of cells containing no actual tissue or organs.