Shrimp make excellent additions to most reef aquariums. These invertebrates are interesting, colorful and many perform important cleaning functions in a tank. Shrimp are scavengers that will eagerly accept small pieces of fish or shrimp in the home aquarium. Shrimp have a hard outer shell and will molt regularly as they grow. Some species form interesting symbiotic pairings with fish, similar to clownfish- anemone pairings.