I ask because I' trying to keep my Mandarin Goby (MG) well fed. Copepods are usually 1 millimeter or less and IMHO constituting mere snack food for a MG. MGs need something bigger like amphipods and Tanaidaceans --3 or 4 millimeters. According to fishbase.org MGs in the wild will eat copepods, amphipods and Tanaidacean. Right now mine is eating the plentiful copepods in my tank and live brine shrimp. (I'm training him to eat enriched, frozen brine shrimp). But the point is, I want to seed and breed the bigger pods in my tank.
Also, the tanaidaceans do live in shallow reefs.