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Marine Animal Encyclopedia

Redlip Blenny Ophioblennius atlanticus


Family: Blennidae

Species: Ophioblennius atlanticus

Species ID: B.OA

Description: Small elongated fish with relatively large eyes, characteristic red lips and reddish pectoral and dorsal fins. Body may be brownish black, pale gray, or have a brown front half with a pale gray rear. Sexes are similar in appearance. Juveniles resemble adults with the addition of faint vertical stripes

Maximum Size: 19 cm (7.5 in)

Longevity: 2 years

Status: Not currently on the IUCN endangered species list

Redlip Blenny & People: Not commercially fished, although when found in by-catch is often used as a bait fish. The redlip blenny is collected to some extent in the Caribbean for export in the aquarium trade


Geographical Range: Very common in shallow water throughout the Caribbean. Range extends north to Georgia, south to Brazil, and also found on reefs along the west coast of Africa

Coral Reef Zone: Common in the back reef, reef flat and sometimes even reef crest zone; may also occur in rocky shore zones. This species can tolerate high wave action because it has developed fins that help it hold on to the reef

Favourite Habitat: Redlip blennies prefer flat coral heads and encrusting coral algae with at least one shelter hole into which they can retreat

Depth Range: 0–8 m (0–27 ft)

A Day in the Life

Dawn: Courtship and spawning take place just after sunrise

Day: Blennies feed on their algal lawn and defend their territory

Dusk: Fish retire to shelters for the night

Night: Blennies hide in shelter holes to avoid nocturnal predators

Who Eats Who

The redlip blenny is a small fish with few defences, and as a result it is preyed upon by virtually any reef predator large enough to swallow it, including grouper and trumpetfish. The redlip blenny itself is strictly herbivorous, eating a variety of reef algae.

Scuba Diver & Snorkeler Best Practices

Participate in scientific underwater assessment projects. Science matters—advanced snorkelers may wish to participate in fish or coral censuses. Assessments such as these help scientists and marine managers take ‘the pulse’ of coral reefs. Not only will you experience the pleasure of snorkeling, but you will also know that you are helping advance knowledge of the ecosystem and aiding in its protection.


These fish are relatively bold. They may initially dart into a reef hole for protection, but usually re-emerge if observers are patient.

Feeding Behaviour

Redlip blennies are herbivores, eating mainly algae and tiny plantlike organisms called epiphytes, which grow on the algae. They usually tend small gardens of algae, which they guard against other herbivores, although not as fiercely as many damselfishes do. During the day, these blennies tend to roll sideways as they feed by on algae.

Observe, record & share:

O B.OA-101 – Feeding: Redlip blennies rip algae from the substrate with a jerking motion

Attack & Defence Behaviour

Redlip blennies defend algae patches and nests inside small territories against other blennies and other small reef creatures. Blennies chase and occasionally bite intruders to drive them away. More serious fights often occur between blenny neighbours, involving fin displays, chasing, biting and even locking jaws and engaging in a shoving match which can last up to 15 seconds. When an intruder appears too large to handle, the blenny will dart into a protective shelter hole to avoid confrontation.

Observe, record & share:

O B.OA-201 – Hiding: Hiding in a shelter hole to avoid confrontation

O B.OA-202 – Territory size: A blenny’s territory is roughly 1m in diameter. They usually swim to the boundary of their territory before returning to their shelter

O B.OA-203 – Territorial dispute: Territorial disputes between blennies typically occur at the limits of their territory, and may involve fin displays, chasing and biting

O B.OA-204 – Mouth-wrestling: In a particularly serious territorial dispute, two blennies may lock jaws and wrestle

Reproductive Behaviour

These blennies reproduce sexually, and do not undergo sexchange during reproductive development. Male blennies clean and prepare a nest hole inside their territory for breeding. Female blennies that are ready to spawn visit the territory of different males, where they display their swollen belly, full of eggs, indicating their readiness to reproduce. The male selects one female and courts her by pecking her on the head and swimming back and forth to his nest, showing her the way. After courtship, eggs are laid in the nest prepared by the male and fertilized. After spawning, males begin guarding and caring for the eggs until they hatch. Spawning occurs in the few hours just after sunrise during the week of the full moon. Spawning is thought to occur year round, with a peak in spring.

Observe, record & share:

O B.OA-301 – Nest location: The location of the male’s favourite hiding place or shelter hole will be the most likely location of its nest

O B.OA-302 – Nest cleaning: Male fish clean a nest by removing debris like rocks and sand

O B.OA-303 – Ripe females: Females display their swollen belly, indicating readiness to spawn

O B.OA-304 – Quivering: Males display in front of their nest hole for passing females and shake briefly to call attention to themselves

O B.OA-305 – Courtship peck: Courting males peck the head of a chosen female to indicate their readiness to spawn

Highlight Behaviors

Courtship: During spawning, female redlip blennies travel up to 5 m ( 16 ft) away from their home territory to find a male with a suitable nest. Several females may assemble at a single nest and elevate their bodies at a 45˚ angle to display their bellies, swollen with eggs. Males decide which female they like best and initiate courtship by pecking the chosen female on her head and leading her back to the nest, where spawning occurs.

Did You Know?

• Male redlip blennies make excellent fathers. They defend eggs against potential predators and fuss over them constantly by removing debris as well as dead or unfertilized eggs. Using a specialized gland located near the tail, male redlip blennies regularly coat the eggs with mucus that prevents fungal and bacterial infection.

• Size does matter for redlip blennies. Females prefer to mate with older and larger males because they are better at defending eggs. Males prefer to mate with older and larger females because they produce more eggs.

• Blenny eggs are less than one millimeter (about 1/16 in) in size when laid. They hatch after 5 days, and spend roughly 45 days drifting as plankton in the ocean before settling back onto the coral reef.

What to do?

Share your observations today!: Discover your species of interest, observe its behaviour, and share your pictures and videos with friends and coral reef enthusiasts around the world! Upload media to the web, tagged with species common name (ex.: trumpetfish) and species ID code (ex.: A.AM) or species behaviour code (ex.: A.AM-101)

Redlip Bennyzoom image
  • Order Blennidae
  • Length 19 cm (7.5 in)
  • Weight Not recorded
  • Depth 0–8 m (0–27 ft)
  • Habitat Found in the reef flat and back reef
  • Distribution Throughout shallow waters in the Caribbean, north to Georgia and south to Brazil
Redlip Benny habitat mapzoom image