The common name "Sailfin Blenny" has been applied to a few species of blenny that look and act in a similar manner. This species, Atrosalarias fuscus, has an elongate body with a high, elongated dorsal fin. A. fuscus has two recognized subspecies, Atrosalarias fuscus fuscus (max. size around 4") and Atrosalarias fuscus holomelas (max. size around 5"), as well as numerous geographical differences.
Their coloration can range from brown to black and may have lighter markings on the face and head. Rarely, a golden yellow color form is also sometimes available and can range from a burnt yellow-brown to bright, vivid gold.
Many different species and varieties of blennies enter the aquarium trade regularly. Some of the more commonly encountered genuses are Atrosalarias (the Sailfin Blennies), Blenniella (Rockskipper or Combtooth Blennies), Ecsenius (often small and flat-faced), Meiacanthus (the notorious fangtooth blennies), and Salarias (the popular algae-eating Lawnmower Blennies). Many blennies may eat some algae growing in the aquarium like the nuisance hair algae, or ornamental macroalgae like Caulerpa. Blennies will also accept many other types of food like pellets, frozen formulas, brine shrimp and others.
Blennies can be kept with most other community tankmates like damsels, clownfish and angels but they may become territorial with time and will defend against trespassers. Blennies typically do not tolerate others of the same species except in very large aquariums with enough territory to accommodate their need for space. They are safe for reef aquariums and will not harm most invertebrates, with the possible exception of small crustaceans like Sexy Shrimp. They spend most of the time on or around the bottom, or perching in the rockwork of the aquarium.