Convict Blenny

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Pholidicthys leucotaenia - Bleeker, 1856
Convict Blenny

Aquarium-born and raised young convict blennies. Alf Jacob Nilsen/Bioquatic Photo


This is an entertaining oddity, a dramatically pigmented eel-like blenny that will mate and even produce young in the aquarium. However interesting, it loves to burrow under rock and can be very rough on an aquarium aquascape.

Other common name(s):

  • Convict Worm Blenny

Native range:

Habitat: Reef-sand interface. Be sure that the rockwork in the tank is stable and resting on the tank bottom (not on the sand), as this species may undermine the reef structure and cause it to collapse.

Maximum length: 34 cm (13 in)

Minimum aquarium size: 114 L (30 gal)

Water: Marine 24 °C (75 °F) - 28 °C (82 °F)

General swimming level: Near substrate.


Carnivore. Feed meaty foods at least once a day.

Aquarium Compatibility

The juveniles can be kept in groups, but remember they grow quite large and can really tear up a tank. Adults are usually congenial to one another and often pair-up. Larger adults will eat small fishes and ornamental crustaceans.


Demersal (on or near the bottom) spawners with larvae lack a pelagic larval stage. They have been known to spawn in the home aquarium producing a benthic egg bundle and then brooding the young, which includes sucking them into their mouths and spitting them back into a favorite crevice. Spawning usually takes place in a cave or burrow and the first sign the aquarist may see is the emergence of the young blennies.


This interesting fish lives in schools as a juvenile, mimicking venomous Coral Catfish (Plotosus lineatus) and spends its time milling about in the water column. As it grows, its stripes shift from longitudinal to vertical and it begins spending time on or near the bottom.

Reference: 101 Best Saltwater Fishes
Image credit: AJN
Text credit: SWM