🐠 Black Sailfin Blenny (Atrosalarias fuscus)
A Striking Solid-Black Body That Stands Out Through Contrast • A Voracious Microalgae Grazer • Best Suited to an Already Established, Algae-Rich Tank
 
📋 The Black Sailfin Blenny, also known as the Highfin Blenny or Dusky Blenny, is a striking solid-black marine fish that stands out through contrast rather than pattern, especially set against lighter rock or sand.
It comes from shallow reef flats, coral beds, and slopes across the Indo-Pacific, including Java, Fiji, the Maldives, and Vanuatu, spending its days grazing steadily across live rock, taking short hops between feeding spots. Every Black Sailfin Blenny we ship is feeding well, and we recommend it for an already established, algae-rich tank, since this species is close to an obligate microalgae eater.
A tank without natural microalgae won't sustain it long-term without consistent supplemental feeding of algae-based foods. It's also a territorial species, best added as one of the last fish to the tank, kept singly unless housed as an established pair, and not combined with other blennies unless the tank is very large with ample hiding spots. Some individuals may nip at small polyp stony corals or clam mantles, so reef compatibility is generally good but not absolute. It reaches up to 14.5cm, so a 115L tank with established microalgae growth suits it well.
 
💡 Highlights
⚫ Striking Solid Black Colouration: Stands out through contrast against rock and sand
🌿 A Voracious Algae Grazer: effective against nuisance hair and string algae
⚠️ A Near-Obligate Microalgae Eater: Needs established algae growth or consistent supplemental feeding
🐟 Territorial: Best added last, kept singly unless an established pair
🌊 Generally Reef Safe: Occasional LPS or clam mantle nipping possible