They are found in most tropical areas staying close within the confines of their protectors reaching arms. Scientist have been puzzled by the name given to this fish, especially since it acts more like a flock of sheep being kept in line by this jelly-like fish. Found in the Nomeidae family from the Perciformes order, the shepherd fish is classified as a ray-finned fish. The shepherd fish is considered one of the smaller marine fish with an approximate length fewer than four inches.
Shepherd fish have sacs along the back part of their throats that are lined with folds of skin.
Each fold encloses a bone structure that supports the skin, which is covered with teeth. The outer skin of the shepherd fish is rather dull in color with either large uneven spots or stripes. This fish is equipped with a rather large pelvic fin that in some species is around three inches in length. Interestingly, the pelvic fin on the shepherd fish will fold inward much like a flag and then tucked away in a groove on the underside. While the protector of the shepherd fish has stinging structures that can paralyze most small fish, the shepherd fish remain immune to the sting even though this jelly-like creature occasionally eats them.