HomeFreshwater aquarium fishGouramis & bettasRoundtail paradisefish Roundtail paradisefish (Macropodus opercularis) Scientific name: Macropodus opercularis Linnaeus, 1758 The Roundtail paradisefish (Macropodus opercularis) is a freshwater fish of the family Osphronemidae that grows to about 7 cm (2.8 in). It is easy to keep and semi-aggressive and needs a tank of at least 115 L (30 US gal), water at 16–26°C (61–79°F) and a pH of 6.0–8.0. Native range: Asia, Korea, eastern Asia, Taiwan, China, Ryukyu Islands: Malacca. Roundtail paradisefish care at a glanceCare levelEasyTemperamentSemi-aggressiveAdult size7 cm (2.8 in)Minimum tank115 L (30 US gal)Temperature16–26°C (61–79°F)pH6.0–8.0Hardness5–19 dGH (89–339 ppm)DietCarnivore. Accepts flakes, freeze-dried foods and frozen foods. BiologyDorsal spines (total): 11 - 17; Dorsal soft rays (total): 5-10; Anal spines: 7 - 22; Anal soft rays: 9 - 15; Vertebrae: 27 - 29. Caudal fin forked, both lobes elongate in males, with filamentous extension in each lobe; lower margin of preorbital sharply serrated; conspicuous dark brown opercular spot with whitish posterior margin (margin red in life); body with 7-11 bold, dark bars on pale yellowish background in preserved specimens (blue bars on reddish background in life); dark stripe crossing eye connecting opercular spot with eye; top of head and predorsal body with dark spots; posterior tip or margin of scales on body not darker than scales.Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameMacropodus opercularisFamilyOsphronemidae (Gouramies)OrderPerciformes (Perch-like fish)ClassActinopterygii (Ray-finned fishes)Maximum length6.7Common length5.5EnvironmentFreshwater;; pH range: 6.0 - 8.0; dH range: 5 - 19 pelagicClimateTropicalDistributionAsia: China, from Yangtze basin to the south, on Hainan Island, in Taiwan, north Viet Nam; introduced to the tropical and subtropical world. Very popular with aquarists and has been widely transported around the world.Conservation status (IUCN)Not EvaluatedThreat to humansHarmlessUsesFisheries: of no interest; aquarium: commercialResilienceHigh, minimum population doubling time less than 15 months (tm More gouramis & bettasSiamese fighting fishBetta splendensCroaking gouramiTrichopsis vittataGiant gouramiOsphronemus goramyBetta albimarginataBetta coccinaPseudosphromenus dayiSee all gouramis & bettas Can it live with...?Roundtail paradisefish and BadisRoundtail paradisefish and Chocolate gouramiRoundtail paradisefish and Crescent bettaRoundtail paradisefish and Croaking gouramiRoundtail paradisefish and Moonlight gouramiRoundtail paradisefish and Ornate ctenopomaRoundtail paradisefish and Pygmy gouramiRoundtail paradisefish and Siamese fighting fishRoundtail paradisefish and Slim bettaRoundtail paradisefish and Spotted bettaRoundtail paradisefish and Spotted ctenopoma SourcesTaxonomy, distribution and biology data: FishBase (Froese, R. and D. Pauly, eds.), licensed CC BY-NC 4.0. Aquarium care parameters compiled, checked and converted to metric and imperial units by Guppies.za.net.Last updated 28 September 2026