Saltwater Fish
Ecsenius bicolor
Ecsenius bicolor - Bicolor Blenny

Ecsenius bicolor (Bicolor Blenny)

Species Description…

Scientific Name: Ecsenius bicolor
Common Name: Bicolor Blenny
Species Group: Blenny
Habitat: Reef Safe
Care Level: Beginner
Temperament: Peaceful
Diet Type: Herbivore
Role in Aquarium: Cleanup Crew
Max Fish Length: 4 (inches)
Min Aquarium Size: 30 (gallons)
Native Range: Indo-Pacific, including the Great Barrier Reef and Indonesia

Overview

  • Native to the Indo-Pacific, commonly found inhabiting shallow coral reefs, rocky slopes, and coastal lagoons.
  • Easily recognized by its distinct two-tone coloration, typically featuring a vibrant blue-black front half and a bright orange-yellow rear half.
  • A playful and inquisitive fish known for its engaging personality and unique swimming style.
  • Frequently seen perched on rocks or coral, observing its surroundings closely.
  • Thrives in aquariums with abundant live rock, ample hiding spots, and consistent water quality.

Feeding

  • Primarily herbivorous, feeding on algae and micro-organisms growing naturally on live rock and coral.
  • Diet should consist of marine algae, dried seaweed, spirulina-based flakes, and herbivore pellets.
  • Occasionally accepts small amounts of frozen or live foods such as mysis shrimp and brine shrimp.
  • Best fed small amounts multiple times daily to match its natural grazing habits.
  • A well-balanced diet rich in algae promotes vibrant coloration, overall health, and longevity.

Habitat

  • Typically found among coral reefs, rocky areas, and lagoon habitats with substantial algae growth.
  • Frequently observed perched atop rock formations or within small crevices, using these spots as vantage points.
  • Aquarium setups should include live rock structures to facilitate natural grazing and hiding behavior.
  • Requires stable water parameters, moderate flow, and high-quality filtration to maintain optimal conditions.
  • Providing numerous hiding places reduces stress and encourages natural behaviors.

Fish Care

  • Optimal water temperature: 72-78°F (22-26°C) to ensure healthy metabolic and immune function.
  • Preferred pH range: 8.1-8.4, maintaining salinity levels at a stable 1.020-1.025.
  • Regular water changes, careful water monitoring, and efficient filtration systems are critical for optimal health.
  • Considered reef-safe, posing minimal risk to corals and most invertebrates.
  • Maintaining algae availability and consistent conditions helps minimize stress and enhance long-term health.

Compatibility

  • Generally peaceful and best housed with other non-aggressive, similarly sized marine species.
  • Compatible with clownfish, gobies, small wrasses, cardinalfish, and other peaceful reef-safe fish.
  • Avoid housing with aggressive or highly territorial species that could cause stress or competition.
  • Suitable for community reef aquariums, where its active personality and beneficial algae-grazing contribute positively.
  • Providing ample hiding and grazing areas ensures harmonious cohabitation with other aquarium inhabitants.

Aquarium Behavior

  • Active and curious, regularly seen perching on rocks or coral structures, closely observing its environment.
  • Exhibits territorial behavior occasionally, particularly when defending favorite perching or hiding spots.
  • Quickly adapts to aquarium conditions, becoming increasingly confident and visible with stability.
  • Providing structured rockwork with natural algae growth encourages typical grazing and exploratory behavior.
  • Over time, it typically recognizes and interacts enthusiastically with its caretaker, particularly during feeding times.