HomeFreshwater aquarium fishRainbowfish & killifishDwarf rainbowfish Dwarf rainbowfish (Melanotaenia praecox) Scientific name: Melanotaenia praecox Weber & de Beaufort, 1922 The Dwarf rainbowfish (Melanotaenia praecox) is a freshwater fish of the family Melanotaeniidae that grows to about 5 cm (2 in). It is easy to keep and peaceful, suits community aquariums and needs a tank of at least 150 L (40 US gal), water at 22–28°C (72–82°F) and a pH of 6.5–7.5. Native range: Indonesia, In small swift flowing jungle streams in the middle sections of the Mamberamo River system in northern Irian Jaya. Dwarf rainbowfish care at a glanceCare levelEasyTemperamentPeacefulCommunity tankGoodAdult size5 cm (2 in)Minimum tank150 L (40 US gal)Temperature22–28°C (72–82°F)pH6.5–7.5Hardness8–18 dGH (143–321 ppm)DietOmnivore. Accepts flakes, frozen foods and live foods. BiologyDorsal spines (total): 5 - 7; Dorsal soft rays (total): 10-14; Anal spines: 1; Anal soft rays: 16 - 21. Develops a very deep body, particularly in males, at a remarkably small size (3.0-3.5 cm SL).Source: FishBase, licensed CC BY-NC 4.0. Species factsScientific nameMelanotaenia praecoxFamilyMelanotaeniidae (Rainbowfishes, blue eyes)OrderAtheriniformes (Silversides)ClassActinopterygii (Ray-finned fishes)Maximum length5.0Common length4.0EnvironmentFreshwater; benthopelagicClimateTropicalDistributionAsia: Mamberamo River in northern Irian Jaya, Indonesia.Conservation status (IUCN)Data deficient (DD)Threat to humansHarmlessUsesFisheries: of no interest; aquarium: commercialResilienceHigh, minimum population doubling time less than 15 months (Preliminary K or Fecundity.) More rainbowfish & killifishForktail rainbowfishPseudomugil furcatusLake Kutubu rainbowfishMelanotaenia lacustrisTami River rainbowfishGlossolepis pseudoincisusRed rainbowfishGlossolepis incisusBlackfin pearlfishAustrolebias nigripinnisJavanese ricefishOryzias javanicusSee all rainbowfish & killifish Can it live with...?Dwarf rainbowfish and Banded rainbowfishDwarf rainbowfish and Black ghostDwarf rainbowfish and Black sharkminnowDwarf rainbowfish and Blackbarred limiaDwarf rainbowfish and Blackfin pearlfishDwarf rainbowfish and Bleeding-heart tetraDwarf rainbowfish and Bloodfin tetraDwarf rainbowfish and Bluespotted corydorasDwarf rainbowfish and Brilliant rasboraDwarf rainbowfish and Butterfly splitfinDwarf rainbowfish and Chinese suckerDwarf rainbowfish and Clown barbDwarf rainbowfish and Clown loachDwarf rainbowfish and Clown rasboraDwarf rainbowfish and Crescent bettaDwarf rainbowfish and Dwarf botiaDwarf rainbowfish and Eel LoachDwarf rainbowfish and Forktail rainbowfishDwarf rainbowfish and Gangetic leaffishDwarf rainbowfish and Garnet tetraDwarf rainbowfish and Glass catfishDwarf rainbowfish and Glowlight tetraDwarf rainbowfish and Goldeneye cichlidDwarf rainbowfish and Head-and-taillight tetraDwarf rainbowfish and Horseface loachDwarf rainbowfish and Indian glassy fishDwarf rainbowfish and Javanese ricefishDwarf rainbowfish and Kamaka rainbowfishDwarf rainbowfish and Lake Kutubu rainbowfishDwarf rainbowfish and Leopard corydoras 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