Blenny fish are part of the order Perciformes and the suborder Blenniodei. “True blennies” exist within six different families of the suborder. Blennies in the Blenniidae family include combtomb and scaleless blennies. The Chaenopsidae family has flag and tube blennies. The Clinidae family has kelpfishes and scaled blennies. The Dactyloscopidae has sand stargazers. The Labrisomidae family has lambrisomid blennies, and the Tripterygiidae family has triplefin blennies. The Clinidae and Blennidae families contain the most species of blennies. Blennies are found anywhere from tropical to cold oceans in various habitats such as rocky pools, sandy beaches, reefs, and beds of kelp. Most are marine fish, but some species can survive in brackish water and freshwater. They’re usually found in shallow water, but they have been spotted as deep as 450 meters underwater. Largely bottom-dwelling fish, only the saber-tooth clade is known to live within the water column. A blenny has a small territory it will use for hiding and sleeping, usually among rocks and other crevices. Described as a calm community fish with a bubbly personality, these fish will likely keep to themselves. They usually will only take issue with another blenny if the environment they share is not large enough to house numerous blennies.
Most blennies are very small and slim with a long dorsal fin. If pelvic fins are present, they will be located near the throat and consist of one spine and two to four rays. Blennies are a longer fish in general, but the tropical species are more moderately elongated while the northern water species are longer and more eel-like. Blennies can be detrivorous, herbivorous, or carnivorous depending on the species. To avoid predators, blennies generally rely on the cover around them and stay hidden. Some species show interesting adaptations such as the ability to hop over rocks from pool to pool when pursued by a predator. A blenny’s coloration may allow it to blend into its surroundings as camouflage. When performing mimicry, some species of blenny can mimic both the coloration and behavior of other fish in order to swim about protected. A type of saber-tooth blenny is capable of mimicking a cleaner wrasse to even get a quick nip out of a larger, unsuspecting fish. Blennies are fun for snorkelers and scuba divers to observe in their natural habitat, and excellent additions to any aquarium. Currently there are no known conservation threats to blennies.