8 kinds · tap one for a closer look
A jumping, surface-hunting predator that needs a tightly covered tank.
This one is best kept on its own, or with its own kind.
A jumping, surface-hunting predator that needs a tightly covered tank. Keep alone or with very large non-aggressive fish; it eats any small fish.
Check your local laws. International: CITES Appendix I since 1 July 1975; trade only in microchipped, documented fish from CITES-registered breeders. USA: listed as Endangered under the Endangered Species Act since 1976, so import, sale and interstate transport are banned (a 2025 petition to allow CITES-farm imports was pending in 2026). Florida also lists it as a Conditional species (no personal possession without permit) and New Mexico prohibits possession by the public. IUCN: Endangered. Check the rules where you live before you buy one, and never release it into the wild.
Not for home aquariums. This fish grows far too big for any home tank. It needs a pond-sized system of thousands of litres, so please don't buy one as a baby.
Large carnivore pellets, crickets, prawns and earthworms; avoid feeder fish that carry disease.
Tap a food to see what it is.
Common problems. Tap one to see the signs. This is a guide, not a diagnosis.
Mouthbrooder (male) ·
Paternal mouthbrooder. After a courtship of weeks to months the female releases a cluster of orange-red eggs, the male fertilises them and takes them into his mouth; they hatch in about a week and the larvae stay in his mouth for another 7-8 weeks. Bred commercially in outdoor pools by registered (CITES) farms in Asia.
Raise 6-8 juveniles together and let a pair form; this takes years.
A 10,000 L+ pond or very large tank with excellent filtration and a secure lid.
Stable warm water and a mature pair of 4+ years.
Small clutches of large eggs (FishBase uses a fecundity of about 50 from concrete-tank breeding). The male broods about 8-9 weeks in all (about 1 week to hatching plus 7-8 weeks with larvae); young are about 6 cm when released.
Fry leave the mouth at 5-6 cm with a yolk sac; feed live food and large pellets and grow them out separately.
A prized Southeast Asian fish, especially popular in eastern Asia for its resemblance to a dragon, symbol of wealth and luck; gold crossback and super red forms are the most coveted. It has been on CITES Appendix I since 1975, so legal international trade is limited to microchipped, documented fish from registered captive-breeding farms. It is Endangered on the IUCN Red List and extirpated across much of its range.
Müller and Schlegel described this fish in 1840 as Osteoglossum formosum. Colour forms are prized in Asia, where it is linked to good fortune. Males brood the eggs and young in their mouths.
First described by Salomon Müller & Hermann Schlegel in 1840. Named for 'formosus' means 'beautiful'.
17 facts checked with sources
Colour forms were split in 2003 as S. legendrei (super red), S. aureus (red-tail golden) and S. macrocephalus (silver forms), but most authors still treat them as S. formosus; Kottelat (2013) suggests the red form may prove distinct. S. inscriptus (Myanmar, 2012) is a separate species. Hybrid forms such as 'Banjar red' are common in trade.
FishBase: Scleropages formosus summary · USFWS Ecological Risk Screening Summary: Asian Bonytongue (Scleropages formosus), rev. Dec 2017, web version 2019 · Seriously Fish: Scleropages formosus (Asian arowana)Legacy has no family.
FishBase: Scleropages formosus summarySeriously Fish 90 cm SL, FishBase 90 cm TL. Australian Dept. of the Environment (via USFWS ERSS) says adults are typically 40-60 cm.
Seriously Fish: Scleropages formosus (Asian arowana) · FishBase: Scleropages formosus summary · USFWS Ecological Risk Screening Summary: Asian Bonytongue (Scleropages formosus), rev. Dec 2017, web version 2019Seriously Fish preferred for husbandry (22-28 °C); FishBase (aquarium atlas) 24-30 °C, which matches legacy.
Seriously Fish: Scleropages formosus (Asian arowana) · FishBase: Scleropages formosus summaryLegacy range lies within Seriously Fish 5.0-8.0.
Seriously Fish: Scleropages formosus (Asian arowana)Legacy has no hardness.
Seriously Fish: Scleropages formosus (Asian arowana)Seriously Fish gives no base footprint ("not recorded"); no litre figure can be computed. Legacy 1,200 L not confirmed.
Seriously Fish: Scleropages formosus (Asian arowana)Quoted by USFWS from Australian Department of the Environment (2014).
USFWS Ecological Risk Screening Summary: Asian Bonytongue (Scleropages formosus), rev. Dec 2017, web version 2019Seriously Fish leaves temperament blank ("Add temperament"), only noting it is kept alone and is not a community fish; FishBase says adults eat fish. No source rates it aggressive.
Seriously Fish: Scleropages formosus (Asian arowana)Seriously Fish rates it moderate, but note it needs a public-aquarium-sized tank (see traits.homeAquarium).
Seriously Fish: Scleropages formosus (Asian arowana)Legacy has no range field. Myanmar (Tenasserim) records may refer to S. inscriptus.
Seriously Fish: Scleropages formosus (Asian arowana) · FishBase: Scleropages formosus summaryClutch size about 50 is consistent with legacy 30-60, but brooding lasts about 8-9 weeks, not 6-8.
FishBase: Scleropages formosus summaryConfirmed. Note that legal import also depends on the destination country (banned in the US; see traits.legal).
Seriously Fish: Scleropages formosus (Asian arowana) · FishBase: Scleropages formosus summaryThe ESA listing date (1976) comes from USAQUA (an industry group) via AMAZONAS; the eCFR 50 CFR 17.11 entry itself could not be fetched. The petition/lawsuit status is as of Feb 2026. State rules are as reported by USFWS in 2019 and may have changed. EU and UK rules were not checked.
USFWS Ecological Risk Screening Summary: Asian Bonytongue (Scleropages formosus), rev. Dec 2017, web version 2019 · Seriously Fish: Scleropages formosus (Asian arowana) · AMAZONAS Magazine (via USAQUA), 20 Feb 2026: USAQUA files intent to sue over Asian arowana imports · AMAZONAS Magazine, 8 Dec 2014: reprint of US Dept. of Justice release on ESA charges (Asian arowana) · FishBase: Scleropages formosus summaryAlso illegal to keep in the US (ESA).
Seriously Fish: Scleropages formosus (Asian arowana)