Bicolor Blenny

Ecsenius bicolor

Animalia›Chordata›Actinopterygii›Blenniiformes›Blenniidae

📍 Indo-Pacific

Distinctive blenny split into two colour halves — dark blue/purple anterior and vivid orange-yellow posterior. Perches on rockwork between short dashes. Algae grazer. Reef-safe but may nip small-polyp corals occasionally.

Size4"

Min Tank30g

peaceful

Zonebottom

Care Guide

Diet

Bicolor Blennies are primarily herbivorous algae grazers that should be offered dried seaweed sheets, spirulina flakes, and algae-based pellets daily. Supplement 2-3 times weekly with small amounts of frozen mysis shrimp or brine shrimp to provide protein variety. A well-established tank with natural algae growth is essential; without sufficient algae, they may nip at small-polyp corals or refuse to eat prepared foods.

Behavior

This blenny is peaceful and relatively sedentary, spending most of its time perched on rockwork or grazing on algae-covered surfaces. They are territorial toward other blennies but generally ignore other fish species. They exhibit characteristic short, rapid dashes between favorite perching spots and may hide when startled, making rockwork with caves essential for their security and comfort.

Breeding

Breeding Bicolor Blennies in captivity is extremely rare and difficult, with very few documented successes in home aquaria. They are broadcast spawners that require specific environmental triggers and larval rearing conditions that are impractical for most hobbyists. Captive-bred specimens are virtually unavailable; nearly all specimens in the hobby are wild-caught.

Tank Mates

Ocellaris Clownfish

Similar peaceful temperament and reef-safe; occupy different tank zones

excellent

Neon Goby

Both small, peaceful bottom-dwellers with minimal aggression toward each other

good

Cleaner Shrimp

Reef-safe invertebrate that occupies different ecological niche; no predation risk

excellent

Pistol Shrimp

Peaceful invertebrate; blenny may ignore or coexist peacefully depending on temperament

good

Nerite Snail

Algae-eating invertebrate that complements blenny's grazing; no competition or aggression

excellent

Common Diseases

Ich (Marine Ich)

Symptoms

White spots on body and fins, rapid breathing, scratching against rockwork, lethargy

Treatment

Increase water temperature to 28-29°C, maintain excellent water quality, use copper-free marine ich treatments or hyposalinity therapy; quarantine if possible

Bacterial Infections

Symptoms

Torn or ragged fins, open sores, cloudy eyes, loss of appetite, color fading

Treatment

Perform 25% water changes, improve water quality, use broad-spectrum antibiotic treatments designed for marine fish; isolate if severely affected

Parasitic Infections (Flukes/Copepods)

Symptoms

Excessive scratching, visible parasites on gills or body, rapid gill movement, weight loss

Treatment

Freshwater dips (30-60 seconds) may provide temporary relief; use marine parasite treatments; maintain pristine water conditions and quarantine new additions

Nutritional Deficiency

Symptoms

Fading coloration, lethargy, reduced appetite, stunted growth, loss of vibrant orange coloring

Treatment

Ensure adequate algae growth in tank; supplement with quality spirulina and algae-based foods; provide varied diet including frozen foods; consider vitamin supplements