Bluestriped Fangblenny (Plagiotremus rhinorhynchos) Care Guide
Plagiotremus rhinorhynchos is an Indo-Pacific fangblenny that mimics the cleaner wrasse and bites scales and mucus from other fish.
Compiled by Aquairi from published sources · Published · Updated
Overview
Plagiotremus rhinorhynchos (Bleeker, 1852) is a combtooth blenny of the family Blenniidae. According to FishBase it reaches about 12 cm in standard length and ranges across the Indo-Pacific. It is best known as an aggressive mimic: it resembles the cleaner wrasse Labroides dimidiatus and uses this disguise to approach larger fish and bite their skin, mucus and scales.
Taxonomy
- Family: Blenniidae
- Genus: Plagiotremus
- Scientific name: Plagiotremus rhinorhynchos (Bleeker, 1852)
Habitat
FishBase records this species from the Indo-Pacific, from the Red Sea south to South Africa and east to the Line, Marquesan and Society islands, north to southern Japan and south to Lord Howe Island. It inhabits clear, coral-rich areas of lagoon and seaward reefs at depths of 1 to 40 m, and when alarmed it hides in deserted worm tubes or other small holes.
Tank requirements
- Minimum tank volume: 200 L (about 53 gal)
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- Carbonate hardness range (record): 8-12 °dGH
- Lifespan: 3-8 years (KB record)
Diet
FishBase and Wikipedia describe the species as feeding on the skin, mucus and sometimes scales of other fishes, which it takes through quick attacks. Unlike true cleaners it provides no cleaning service. This diet makes it challenging to maintain alongside other fish.
Compatibility
Because it bites the scales and mucus of tank mates, this species can harass other fish despite its small size. FishBase and Wikipedia note that its mimicry of Labroides dimidiatus is facultative and frequency-dependent, working best where the mimic is rare relative to genuine cleaners. Keepers should avoid combining it with delicate or slow-moving fish; the KB record lists clownfish, tangs, cardinalfish and wrasses as community options and large predators such as lionfish and triggers as fish to avoid.
Conservation status
IUCN Red List: Least Concern, assessed in 2009.
Breeding the Bluestriped Fangblenny (Plagiotremus rhinorhynchos)
Overview
Plagiotremus rhinorhynchos (family Blenniidae), the bluestriped fangblenny, ranges throughout the Indo-Pacific and reaches about 12 cm standard length at depths of 1-40 m. FishBase notes it feeds on the skin, mucus and sometimes scales of other fishes by quick attacks, and that juveniles mimic the cleaner wrasse Labroides dimidiatus. Adults shelter in deserted worm tubes and small holes.
Sexing
FishBase records the species as oviparous with distinct pairing. No reliable external sexing characters are documented for the aquarium, so a compatible male-female pair is recognised by pairing and the shared occupation and defence of a tube refuge.
Breeding Setup
A breeding attempt requires a species-appropriate system with narrow tubes or holes the fish can retreat into and defend, mirroring the deserted worm tubes it uses in the wild. Because it bites the mucus and scales of tankmates, it should be kept without vulnerable fish during breeding trials.
Spawning Behavior & Trigger
Reproduction follows the blenny pattern of distinct pairing, with the female depositing eggs inside a tube or hole that the male typically fertilises and guards. The tubular refuge the fish uses for shelter serves as the spawning site.
Egg & Fry Care
Eggs are demersal and adhesive, attached to the substrate by a filamentous adhesive pad or pedestal, and larvae hatch as planktonic forms found in shallow coastal waters. Rearing these larvae requires a dedicated larval system and graded live foods.
Common Challenges
Beyond the difficult planktonic larval phase, the species' habit of biting the mucus and scales of other fish makes it hard to house with the tankmates a community breeding system would otherwise allow, and emerging fry behavior is poorly documented.