HomeFish encyclopediaRay-finned fishesCatfishSea catfishesDark sea catfish Dark sea catfish (Cathorops melanopus) Scientific name: Cathorops melanopus G?nther, 1864 The Dark sea catfish (Cathorops melanopus) is a freshwater fish of the family Ariidae. BiologyDorsal spines (total): 1; Dorsal soft rays (total): 7; Anal soft rays: 19 - 20. Distinguished from all other species of Cathorops by the possession of the following features: gill rakers on first arch 16-18; anal fin with 19-20 rays; snout length 5.3-5.5% SL; and posterior margin of pectoral-fin spine with prominent serrations, except in Cathorops aguadulce, Cathorops kailolae, Cathorops multiradiatus, and Cathorops tuyra. Can be further differentiated from other congeners by the following combination of characters: distance from tip of snout to dorsal-fin origin 30.0-32.6% SL; distance from tip of snout to posterior margin of dorsomedian groove of neurocranium 17.9-19.1% SL; absence of fleshy papillae intercalated with gill rakers on first two arches; head length 22.3-23.0% SL; distance between lateral cornu of lateral ethmoid and external limb of supracleithrum 19.3-19.6% SL; distance between the anterior nostrils 3.6-4.4% SL; distance between posterior nostrils 4.4-5.1%Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameCathorops melanopusFamilyAriidae (Sea catfishes)OrderSiluriformes (Catfish)ClassActinopterygii (Ray-finned fishes)Maximum length23.0EnvironmentFreshwater; benthopelagicClimateTropicalDistributionCentral America: Rio Motagua, Guatemala; probably in the Honduran portion of the rio Motagua near itsmouth. Reports from Mexico, Nicaragua, Costa Rica and Panama by previous authors are erroneous.Conservation status (IUCN)Not EvaluatedThreat to humansTraumatogenicResilienceMedium, minimum population doubling time 1.4 - 4.4 years (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