Actinopteri (ray-finned fishes) > Acanthuriformes
(Surgeonfishes) > Siganidae
Etymology: Siganus: Latin, siganus = a fish, rabbit fish; by the similarity of the nose (Ref. 45335); insomnis: Name from Latin 'insomnis' meaning sleep-less; referring to the nocturnal activity of this fish. It is an adjective agreeing in gender with Siganus (masculine).
Environment: milieu / climate zone / depth range / distribution range
Marine; reef-associated. Tropical
Indian Ocean: southern India, Sri lanka and the Maldives.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 35.0 cm SL male/unsexed; (Ref. 95994)
Morphology | Morphometrics
soft rays: 9. This deep-bodied species is distinguished from other siganids in that the whole of the sides of the body with the possible exception of the belly and a narrow strip adjacent to the base of the spinous dorsal fin (where a row of bronze spots may occur), are decorated with horizontal, parallel bronze bands extending the full length of the sides from nape and opercular slit back to and below the large yellow spot below the base of the soft dorsal fin; majority of these lines on the sides are complete (uninterrupted) along their length (Ref. 95994).
Adults live in schools, usually in coral and sandstone reefs and also seagrass beds; juveniles reportedly live in large estuaries such as Negombo Lagoon (5 km x 3 km). Apparently, estuaries are an important habitat for juveniles and sub-adults, with older fish moving to coral reefs. Feeds by scraping algae from rock and coral substrates and browsing on seaweeds and sea grasses. It supplements its diet with small items of animal tissue. A report on analysis of gut contents of specimens (2 - 27 cm SL), collected by trap and seine, from lagoons and coastal areas of Sri Lanka contain diatoms, green, blue-green, red and brown algae and a seagrass. It appeared that this species have a preference for feeding during the night when percentages of gut fullness between day and night catches were compared. It appeared to be nocturnal because it was mostly seen to be inactive during the day (Ref. 95994).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Woodland, D.J. and R.C. Anderson, 2014. Description of a new species of rabbitfish (Perciformes: Siganidae) from southern India, Sri Lanka and the Maldives. Zootaxa 3811(1):129-136. (Ref. 95994)
IUCN Red List Status (Ref. 123251)
CITES (Ref. 123416)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01622 (0.00713 - 0.03687), b=3.06 (2.87 - 3.25), in cm total length, based on LWR estimates for this Genus-body shape (Ref. 93245
Resilience (Ref. 120179
): High, minimum population doubling time less than 15 months (Preliminary K or Fecundity.).
Vulnerability (Ref. 59153
): Low to moderate vulnerability (27 of 100) .