HomeFish encyclopediaRay-finned fishesPerch-like fishThreefin blenniesTwister Twister (Bellapiscis medius) Scientific name: Bellapiscis medius G?nther, 1861 The Twister (Bellapiscis medius) is a marine fish of the family Tripterygiidae. Native range: Southwest Pacific, endemic to New Zealand. BiologyDorsal spines (total): 18 - 21; Dorsal soft rays (total): 10-14; Anal spines: 2; Anal soft rays: 20 - 23Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameBellapiscis mediusFamilyTripterygiidae (Threefin blennies)OrderPerciformes (Perch-like fish)ClassActinopterygii (Ray-finned fishes)Maximum length7.5Depth range0–5 m (0–16 ft)EnvironmentMarine; demersal; non-migratory; depth range 0 - 5 mClimateTemperateDistributionSouthwest Pacific: endemic to New Zealand.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessUsesFisheries: of no interestResilienceHigh, minimum population doubling time less than 15 months (Preliminary K or Fecundity.) SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0.Last updated 27 September 2026