Fellow Creatures
Saltwater Fish

Midas Blenny

Ecsenius midas

Golden, eel-like swimmer with bold charm  ·  Beginner

Midas Blenny

BEDO (Thailand) · CC BY-SA 4.0 — Wikimedia Commons

Lifespan
4-6 years
Adult size
10-13cm (4-5in)
Min. habitat
Aquarium 110L+ / 30gal+
Social needs
One per tank unless a bonded pair
Diet
Omnivore, zooplankton and algae
Time
Low
Cost
Medium

Overview

  • The Midas Blenny is a golden-yellow fish with bright eyes and a graceful, eel-like swimming style unusual among blennies.
  • Hardy and personable, it is a good beginner marine fish that often hovers in open water rather than perching.
  • Unlike many blennies it is a midwater feeder that associates with the anthias it naturally schools with.
  • It can shift colour from gold to bluish depending on mood and surroundings.

Housing

  • Provide a reef tank of at least 110L (30 gallons) with live rock offering caves and crevices it can dart into and claim.
  • It favours a hole or tube as a base from which it watches the tank.
  • Maintain temperature 24-27C (75-81F), salinity 1.024-1.026, pH 8.1-8.4, and ammonia and nitrite at zero.
  • A secure rockwork retreat makes for a confident, frequently visible fish.

Diet

  • An omnivore that feeds largely on zooplankton in the water column, supplemented by some algae.
  • Offer frozen mysis and brine shrimp, marine flakes and pellets, and algae-based foods one to two times daily.
  • It readily accepts prepared foods and is an enthusiastic feeder, making it easy to keep well-nourished.
  • A varied diet maintains its golden colour and active behaviour.

Health

  • Hardy and adaptable, with fewer disease problems than many marine fish, though quarantine is still wise.
  • Stable water and a varied diet keep it healthy and brightly coloured for years.
  • Watch for hiding, faded colour, or refusal to eat as early warning signs.
  • Most issues arise from poor water quality, aggressive tankmates, or an immature tank rather than inherent fragility.

Temperament

  • Peaceful toward most species but territorial toward other blennies and sometimes similar-shaped fish.
  • Keep one per tank unless you obtain a bonded pair, as two unpaired individuals may fight.
  • It is bold and outgoing once settled, often hovering in the open and interacting with its keeper.
  • Reef-safe with corals and invertebrates, it integrates smoothly into peaceful community systems.

A good fit for

  • Beginners wanting a hardy, active fish
  • Reef community tanks needing midwater interest
  • Keepers wanting an outgoing, visible fish
  • Peaceful reefs with corals and inverts

Common mistakes to avoid

  • Two unpaired blennies will fight
  • Needs a secure rock retreat to settle
  • Can jump; a tight-fitting lid helps
  • Aggressive tankmates may bully it
Open in the interactive browser → Find an ethical store Find an exotic vet

More Saltwater Fish guides

Ocellaris Clownfish
Ocellaris Clownfish
Amphiprion ocellaris
Beginner

Hardy, beginner-friendly reef-tank clownfish

6-10 yearsRead guide →
Royal Gramma
Royal Gramma
Gramma loreto
Beginner

Purple-and-gold peaceful reef basslet

5-7 yearsRead guide →
Firefish Goby
Firefish Goby
Nemateleotris magnifica
Beginner

Slender dartfish with a flicking dorsal flag

3-5 yearsRead guide →
Yellow Watchman Goby
Yellow Watchman Goby
Cryptocentrus cinctus
Beginner

Sand-sifting goby that shares a pistol-shrimp burrow

4-6 yearsRead guide →
Pajama Cardinalfish
Pajama Cardinalfish
Sphaeramia nematoptera
Beginner

Peaceful nocturnal cardinalfish that lives in groups

4-5 yearsRead guide →
Green Chromis
Green Chromis
Chromis viridis
Beginner

Active blue-green shoaler for a peaceful reef

8-15 yearsRead guide →