You may have heard of these Copepod things. Copepods are small crustaceans found in both fresh and saltwater. There are thousands of species of copepods, some good and some bad. The majority of copepods found in the typical saltwater fish tank are beneficial to the aquarium.

Another larger organism, similar to a copepod, is an amphipod. Like copepods, amphipods also provide a food source for fish and other invertebrates. Many aquarists want a large population of copepods and amphipods to provide a free living food source to their inhabitants.

Imparticular, copepods are the primary food source for Mandarin Dragonets. These spectacular fish can quickly strip a small aquarium of its copepods. Although most copepods are self-culturing in the Live Rock, many aquarists will create a Refugium to help maintain their pod population.