HomeFreshwater aquarium fishOther freshwater fishRoundbelly cowfish Roundbelly cowfish (Lactoria diaphana) Scientific name: Lactoria diaphana Bloch & Schneider, 1801 The Roundbelly cowfish (Lactoria diaphana) is a brackish-water fish of the family Ostraciidae. BiologyDorsal spines (total): 0; Dorsal soft rays (total): 9; Anal spines: 0; Anal soft rays: 9. Small spine on back and short spines before eyes. Caudal fin rays 10.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameLactoria diaphanaFamilyOstraciidae (Boxfishes)OrderTetraodontiformes (Puffers and Filefishes)ClassActinopterygii (Ray-finned fishes)Maximum length34.0Depth range8–50 m (26–164 ft)EnvironmentMarine; brackish; reef-associated; depth range 8 - 50 mClimateSubtropicalDistributionSoutheast Atlantic: off Swakopmund, Namibia. Indo-Pacific and Eastern Pacific: South Africa east through Indonesia to the Easter Island and Peru, north to southern Japan, Hawaii, and southern California, south to New Caledonia, New South Wales and Kermadec Islands.Conservation status (IUCN)Not EvaluatedThreat to humansVenomousUsesFisheries: of no interest; aquarium: commercialResilienceHigh, minimum population doubling time less than 15 months (Fec assumed to be > 10,000) More other freshwater fishSouth American lungfishLepidosiren paradoxaLined soleAchirus lineatusPumpkinseedLepomis gibbosusShort-tailed pipefishMicrophis brachyurus brachyurusFinescale tigerfishDatnioides microlepisFreshwater garfishXenentodon cancilaSee all other freshwater fish SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0.Last updated 27 September 2026