Bicolor blenny

Ecsenius bicolor · Blenniidae

Also known as Two-colour blenny

Beginner

Half brown, half orange, and it perches everywhere; occasionally nips coral when underfed.

In short: A bicolor blenny needs at least 110 L (29 US gal), water at 23–27 °C (73–81 °F) and pH 8.1–8.4. It is semi-aggressive, usually kept singly, and rated beginner to keep.

Updated 6 October 2026

Minimum tank: 110 L (29 US gal)
Temperature: 23–27 °C (73–81 °F)
pH: 8.1–8.4
Adult size: 10 cm (3.9 in)
Group size: 1+

Reef & marine husbandry

Specific gravity: 1.023–1.026
Reef safety: Reef safe with caution
With corals: May nip clam mantles and zoanthids if algae is scarce.
With inverts: Reef safe.
Minimum in a mixed reef: 110 L (29 US gal)
Minimum fish-only (FOWLR): 110 L (29 US gal)
Aggression: Chases similar-shaped fish from its perch.
Feeding: Algae available all day plus daily feeds.

Care requirements

Minimum tank volume: 110 L (29 US gal)
Temperature: 23–27 °C (73–81 °F)
pH: 8.1–8.4
Hardness: 8–12 dGH
Lifespan: 2–6 years
Diet: Omnivore — algae, nori, mysis, pellets.
Care level: Beginner

Origin & habitat

Native region: Indo-Pacific
Water type: Saltwater
Biotope: Rocky reef with algae film
Natural conditions: Mature rock, moderate flow.

Behaviour & stocking

Temperament: Semi-aggressive
Minimum group: 1 fish
Swims: Bottom
Good tank mates: Clownfish
Cardinalfish
Tangs
Avoid: Other Ecsenius blennies
Small gobies in nano tanks

Breeding & difficulty

Breeding difficulty: Advanced
Sexing: Males are larger with brighter colour.
Notes: Rarely bred.
Common ailments: Marine ich
Starvation

Will it fit your tank?

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