This long and scaleless fish has a “horseface†appearance, thus the name.  Their bodies are dark reddish brown and they have red lips, a red tail fin and red on the outer edges of the pectoral fins. Sometimes they are a pale pinkish gray which is the color morph that is confused with it’s smaller sister fish, the Redlip Blenny, O. macclurei, who happens to inhabit the same areas in the Western Atlantic.  At night, the Horseflace Blenny develops dark and light mottling to blend in with the rock wo.  Similar to other blennies, they may live up to 6 years and grow to 7.5†(19 cm), which is probably the larger male size.

   The Horseface Blenny which grows to 7.5,†is often confused with the Atlantic Redlip Blenny, or officially, the Redlip Blenny, which is smaller, only growing to 4.7†or 12 cm.  This smaller blenny is lighter in color with a dark reddish brown head and is typically misnamed as O. atlanticus. The Horseface Blenny is another comb-tooth blenny with a few extra fangs added to their mouth.  Their scientific name is Greek for “mucus serpent,†due to their scaleless and slimy bodies.  Another feature they have are two long sharp canine fangs.  They will change in color from their solid daytime color to a pale and dark mottled pattern while they sleep.  Horseface Blenny males also excrete a microbial mucus over their eggs to protect them. 

   These hardy, yet aggressive blenny can inflict a wound due to their long sharp canine teeth, so caution needs to be exercised while the aquarists hands are in the tank.  They are fine for the beginner aquarist who has a matured tank growing plenty of algae and is also wary of those sharp teeth. Growing macro algae in a separate tank can be added to supplement their diet if the algae population drops.  Although they are disease resistant, any fish can fall victim to bacterial infections or parasites if the water quality is low. Avoid medications that are dangerous for scaleless fish. 

   This blenny has  long sharp fangs and is NOT afraid to use them!  They will bite and attack other fish twice it’s size!  They will aggressively protect their territories and should not be housed with peaceful fish or small fish.  Do not house with other blennies or peaceful gobies.  Avoid housing them with fish large enough to eat them.  Fish should be semi-aggressive to aggressive and at least twice as large as they are.

   The minimum tank size is 75 gallons because of their very aggressive nature and larger 7.5†size.  These 2 factors, coupled with their need to eat large amounts of algae, requires a larger tank that can keep up with the algae consuming demands of this fish.  If adding other algae eaters, the tank should be larger to provide enough food.  Provide enough light to promote algae growth.  Grow some macro-algae in a separate tank to provide supplemental food in addition to the algae growing in the tank.  They can tolerate steady temperatures from 72 to 79ËšF.  They like the bottom section of the tank and water movement should be moderate since they inhabit areas where there is good wave motion.

Picture of a Red-lipped Blenny during the day.
Ophioblennius atlanticus

Coloration at night

For more Information on keeping this fish see:
Guide to a Happy, Healthy Marine Aquarium

Scientific Classification

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Perciformes
  • Family: Blenniidae
  • Genus: Ophioblennius
  • Species: atlanticus
Horseface Blenny, Ophioblennius atlanticus

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Close up of Horseface Blenny

This is a great video showing the “horsey” face with the red outer edges of the pectoral fins. They are a darker fish and become mottled at night or when they are afraid. The lighter version is often confused with their 4.7″ sister blenny which is actually the TRUE Redlip Blenny, that inhabits the same areas in the Western Atlantic as the Horseface Blenny. The Horseface Blenny grows to 7.5″ and it will attack fish over 2ce their size. These blennies have long sharp fangs that will inflict a wound on any fish that wanders close to their territory, as well as a hand passing by! Small specimens are not as aggressive as larger adults.

Red-lipped Blenny – Quick Aquarium Care

  • Aquarist Experience Level: Beginner
  • Aquarium Hardiness: Very Hardy
  • Minimum Tank Size: 75 gal (284 L)
  • Size of fish – inches: 7.5 inches (19.05 cm)
  • Temperament: Aggressive
  • Temperature: 72.0 to 79.0° F (22.2 to 26.1° C)
  • Range ph: 8.0-8.3
  • Diet Type: Omnivore

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Habitat: Distribution / Background

   The Horseface Blenny, Ophioblennius atlanticus, was first described by Valenciennes, in 1836.  The genus name, Ophioblennius is Greek for “serpent†and the species name derived from blennios is Greek for “mucus,†making or little friend a mucus serpent!   The common names they are known by are Devilfish and Redlip Blenny and unofficially Horseface Blenny and and Atlantic Red-Lip Blenny since it inhabits both the east and west atlantic coasts, however their sister blenny holds that name in the official list to add to the confusion.

   Horseface Blennies are found throughout both sides of the Atlantic Ocean’s coasts.  In the Eastern Atlantic, they are found along the west coast of Africa from Senegal to Angola.  In the Western Atlantic, they are found in Bermuda and North Carolina (USA) and then south throughout the Caribbean to Brazil, although rare in northern Gulf of Mexico.  They inhabit shallow waters as adults, dwelling within coral reefs and rocks where there is good water movement from waves.  Horseface Blennies are found from 2 to 26 feet in depth (2 to 8), although larvae are found much deeper in the water column.  In the Eastern Atlantic areas, they are reported at 39 feet (12 meters).  These blennies feed mostly on filamentous algae, however they also feed on zooplankton, plankton and other inverts and occassionally on detritus.  Larvae feed on plankton, then when morphing into the adult shape during their final stage, they do not eat and depend on stored fat in their livers.  These fish cohabit with the smaller 4.7†lighter Redlip Blenny, (Ophioblennius macclurei) in the Western Central Atlantic. 

   The Horseface Blenny is on the IUCN Red List for Least Concern with an unknown population trend.  There are no known threats and have a widespread population.

   Redlip Blenny (Ophioblennius macclurei):  This blenny has the reddish brown head and pale body.  It is found in some of the same areas as the larger Horseface Blenny in the Western Atlantic.  The confusion lies with the lighter color morph of a young Horseface Blenny, often being mistaken for one another.  The true Redlip Blennies are much smaller, only growing to 4.7.†

  • Scientific Name: Ophioblennius atlanticus
  • Social Grouping: Solitary
  • IUCN Red List: LC – Least Concern – With unknown population trend.


  The Horseface Blenny is an elongated, scaleless fish with a dark reddish brown body.  They have red lips, red tail fins and red on the outer areas their pectoral fins.  Sometimes they are a pale pinkish gray with the same reddened areas.  These blennies are from the combtooth blenny group, named due to their comb-like teeth.  These teeth, which are found in their downturned mouth, can easily scrape algae off hard surfaces. They also have long, sharp canine teeth that they use to defend themselves.  Males are larger and have fleshy capped anal-fin spines.  Similar to other blennies, they may live up to 6 years and grow to 7.5†(19 cm), which is probably the larger male size.

  • Size of fish – inches: 7.5 inches (19.05 cm)
  • Lifespan: 6 years – May be similar to other combtooth blennies such as the Lawnmower Blenny

Fish Keeping Difficulty

   These larger blennies are very hardy as long as the tank is matured and has plenty of algae production to feed from.  Starvation is their weakness, yet simply supplementing them with macro algae grown in another tank or algae sheets can go a long way.  The larger 75 gallon tank size is for their benefit, since this will help keep them supplied with food and will benefit tank mates as these fish are known to attack fish that are twice as big as they are, as they aggressively defend their territory in the tank.  If housing with other algae eating creatures, the tank should be 75 gallons or more.  They will stay healthy with decent water parameters and do need a decent flow, since they are found in areas that have good wave action in the wild.

  • Aquarium Hardiness: Very Hardy
  • Aquarist Experience Level: Beginner

Foods and Feeding

   The Horseface Blenny is an omnivore.  Stomach contents from Fishbase reveal zooplankton and other planktonic inverts.  They have also been recorded as eating filamentous algae and detritus.  Feed them flake and sinking pellets for omnivores if there is plenty of algae in the tank, or flake and sinking pellets for herbivores if algae levels are low.  Also try various types of algae clips.  They will also eat mysis, enriched brine shrimp and finely minced table shrimp.  Pay attention to what they eat or reject (eat then spit out) to hone in on their preferences.  Feed several times a day with most of the diet being veggie foods. 

  • Diet Type: Omnivore
  • Flake Food: Yes – Flake for herbivores. Omnivore formula with algae present in the tank.
  • Tablet / Pellet: Yes – Sinking pellets for herbivores. Omnivore formula with algae present in the tank.
  • Vegetable Food: Most of Diet
  • Meaty Food: Some of Diet
  • Feeding Frequency: Several feedings per day

Aquarium Care

Reef tanks:

  • Medium sized up to 90 gallons, perform 15% bi-weekly. 
  • Large Tanks 100 gallons and over, once water is aged and stable can be changed 10% bi-weekly to 20% monthly, depending on bioload.

Fish only tanks:*

  • Medium sized up to 90 gallons, perform 20% to 30% monthly depending on bioload. 
  • Large Tanks 100 gallons and over, once water is aged and stable can be changed 20% to 30% every 6 weeks depending on bioload.

For more information on maintaining a saltwater aquarium see: Saltwater Aquarium Basics: Maintenance. A reef tank will require specialized filtration and lighting equipment. Learn more about reef keeping see: Mini Reef Aquarium Basics.

*Note:  If this is the ONLY fish in the tank, with no corals or other fish you can get away with less water changes of 20% monthly.

  • Water Changes: Bi-weekly

Aquarium Setup

   Minimum tank size of 75 gallons.  Provide live rock with a lot of surface area exposed to moderate light to promote algae growth.  Any substrate is acceptable and they are fine in temperatures from 72 to 79ËšF and normal 8.0 to 8.3 pH.  Create moderate water movement, since they prefer natural habitat with wave movement in the wild.  They are usually found at the bottom parts of the tank.  These fish should be kept as the only blenny in the tank because they will attack other blennies unless the tank is over 125 gallons.  They can be kept in a 75 to 100 gallons if they are a male and female pair.

  • Minimum Tank Size: 75 gal (284 L)
  • Suitable for Nano Tank: No
  • Live Rock Requirement: Typical Amount
  • Substrate Type: Any
  • Lighting Needs: Moderate – normal lighting – Enough to produce sufficient algae growth.
  • Temperature: 72.0 to 79.0° F (22.2 to 26.1° C)
  • Breeding Temperature: – Unkown
  • Specific gravity: 1.023-1.025 SG
  • Range ph: 8.0-8.3
  • Brackish: No
  • Water Movement: Moderate
  • Water Region: Bottom

Social Behaviors

   The Horseface blenny is aggressive, however they ignore other fish unless they come into it’s territory.  They will attack others of their own kind unless the tank is 125 gallons or more, allowing the fish enough territory to reign over.  They can be housed as a male/female pair in a tank that is over 75 gallons in order to provide enough food for both.

   These blennies should not be housed with any fish that is not at least twice their size. This goes for semi-aggressive or aggressive fish, also avoiding fish that are also bottom dwellers, unless tank is well over 100 gallons.  While they ignore most tank mates, any that venture near their territory will be met with a fierce response.  Usually, it is one of those “friendly†fish that just wants to check the blenny out, and ends up with a bite hole in their side!  Horseface Blennies are fine with larger peaceful fish that are over 2 times their size, and inhabit the top of the tank.  They are great in tanks with more aggressive fish like large dottybacks and triggerfish, taking care of algae issues that a Lawnmower Blenny could never survive in, because they are too mellow.  Your Horseface Blenny will hold  his own against other fish, resorting to biting with their long sharp fangs if the intruder doesn’t take a hint! Keep an eye on any wounds your blenny may inflict on tank mates or your hand! Do not house with fish that are large enough to swallow your blenny. 

  In a reef, they may pick at stony corals if they are not well fed.  Most noxious soft corals and polyps and the like should be okay.

  Most inverts are safe, although a hungry Horseface Blenny may pick at clam mantles.  Avoid small shrimp like Sexy Shrimp.

  • Venomous: No
  • Temperament: Aggressive
  • Compatible with:
    • Same species – conspecifics: Sometimes – Male/female pair. Or in tanks that are 125 gallons or more.
    • Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Threat
    • Semi-Aggressive (anthias, clownfish, dwarf angels): Threat
    • Monitor – Should be twice the size of the Horseface Blenny.
    • Large Semi-Aggressive (tangs, large angels, large wrasses): Safe
    • Large Aggressive, Predatory (lionfish, groupers, soapfish): Threat
    • Threat
    • Anemones: Safe
    • Mushroom Anemones – Corallimorphs: Safe
    • LPS corals: Monitor – May nip at the polyps if hungry.
    • SPS corals: Monitor – May nip at the polyps if hungry.
    • Gorgonians, Sea Fans: Safe
    • Leather Corals: Safe
    • Soft Corals (xenias, tree corals): Safe
    • Star Polyps, Organ Pipe Coral: Safe
    • Zoanthids – Button Polyps, Sea Mats: Safe
    • Sponges, Tunicates: Safe
    • Shrimps, Crabs, Snails: Safe
    • Starfish: Safe
    • Feather Dusters, Bristle Worms, Flatworms: Safe
    • Clams, Scallops, Oysters: Monitor – May nip at clam mantles if not well fed.
    • Copepods, Amphipods, Mini Brittle Stars: Safe

Sex: Sexual differences

   The male is usually larger. It is thought that the male has an extra black edge on the ventral and tail fins.  Males also have extra flesh on the tips of their anal-fin spines.

Breeding / Reproduction

   A female Horseface Blenny will deposit her eggs on the substrate with a filamentous adhesive pad or pedestal.  The male will quickly fertilize them and then secrete an antimicrobial mucus on the eggs.  Males guard their clutch until they hatch.  Once the larvae hatch, they have already developed terminal mouths and fang like teeth.  They then move deeper into the water column and feed on plankton.  When it is time for the larvae to take on their fish form, they stop eating and depend on fat stored in their liver to survive during this host metamorphosis.  Once they are adults, they swim up to in shallower waters.  

   They have not been bred in captivity to date. (Jan 2015)

  • Ease of Breeding: Unknown

Fish Diseases

   The Horseface Blenny is disease resistant.  There are no special directions for treating them with common illnesses, however, do not treat them with medicines that are dangerous for scaleless fish. 


   Horseface Blennies are easy to find online and in stores, around $30.00 USD (Jan 2015).


Animal-World References: Marine and Reef

By Scott W. Michael
T.F.H. Publications
Copyright © 2001 by T.F.H. Publications, Inc.

By Scott W. Michael
T.F.H. Publications
Copyright © 2005 by T.F.H. Publications, Inc.


by Bob Goemans
Ophioblennius atlanticus
Atlantic Red-lip Blenny

Author: David Brough. CFS.

 Ophioblennius atlanticus (Image Credit: Quintín Muñoz, Wikimedia Commons GPL 3.0)