Asian Arowana Care Guide: The Ultimate Guide to the Dragon Fish

Species Overview#

The Asian arowana (Scleropages formosus) is the most expensive aquarium fish on the planet, and the most legally complicated one a hobbyist can chase. A high-grade Super Red can fetch tens of thousands of dollars at auction in Singapore, gets implanted with a CITES microchip at the farm, and travels with paperwork that would not look out of place on a thoroughbred horse. It is also, for any reader inside the United States, a fish you cannot legally buy, sell, or own — a detail that catches a surprising number of monster-fish hobbyists off guard.

This guide covers what the fish actually needs to thrive in a glass box, why the species has the cultural and legal weight it carries, and — for US readers — which legal "Dragon Fish" alternatives can scratch the same itch without a federal felony attached. If you are reading this from somewhere it is legal to keep one, the husbandry section is the part you came for. If you are reading from the US, skip ahead to the Legal Landscape and Legal Alternatives sections before you get attached to the idea.

Adult size

30-36 in (75-90 cm)

Lifespan

20+ years

Min tank (adult)

250-300 gallons

Temperament

Aggressive, territorial

Difficulty

Expert only

Diet

Surface carnivore

The "Dragon Fish" Symbolism and Varieties (Super Red, Crossback Golden, Banjar Red)#

The arowana's elongated body, large pectoral fins, and upturned mouth give it a striking resemblance to the dragons of Chinese mythology — long, sinuous, and barbeled. That visual cue, combined with the fish's metallic scales and slow, deliberate swimming, is why Scleropages formosus is treated as a living luck charm in much of East and Southeast Asia. A red Asian arowana in a businessman's lobby tank is not decoration. It is feng shui hardware.

The hobby recognizes several major color strains, all of which are the same species:

• Super Red: The most prized variety. Native to the Kapuas River and Lake Sentarum in West Kalimantan, Indonesia. Adult specimens develop deep, blood-red scales across the entire body, gill plates, and fins. Sub-grades include Chili Red, Blood Red, and Orange Red, with Chili Red commanding the highest prices.
• Crossback Golden: From Bukit Merah and the Perak River in Malaysia. The defining trait is full metallic gold scaling that crosses the dorsal ridge — hence "crossback." Lower grades, where the gold stops short of the back, are sold as 24K, while full crossbacks are graded by base color (purple, blue, or green base).
• Banjar Red: A hybrid-looking lower-grade strain from the Banjarmasin region of Indonesia. Often sold to first-time arowana buyers as "Red Arowana" without the Super Red price tag. It will not develop the deep red of a true Super Red — expect more of a salmon-orange.
• Red Tail Golden (RTG): A separate Indonesian gold strain. Body scales go gold, but the back stays dark and the tail turns red — never a true crossback.
• Green Asian Arowana: The least valuable variety, native to several Southeast Asian countries. Olive-green base, dark dorsal stripe, and the lowest CITES paperwork burden of the bunch.

Color development is slow. A juvenile Super Red looks like a silver fish with a faint pink lip. The full red coloration takes three to five years to develop and depends heavily on diet, lighting (warm spectrum lights are used to "pump" color), and tank background color.

Understanding CITES I Status and ESA Regulations in the US#

Scleropages formosus is listed on CITES Appendix I, the strictest tier of international wildlife trade protection, alongside species like the giant panda and the snow leopard. Appendix I means commercial trade in wild-caught specimens is prohibited globally. Captive-bred specimens from CITES-registered farms can be traded internationally, but every single fish must be individually microchipped, accompanied by a CITES export permit from the country of origin, and a matching CITES import permit from the destination country.

The United States layers a second restriction on top. The US Fish and Wildlife Service lists the Asian arowana as endangered under the Endangered Species Act (ESA). The ESA prohibits import, export, interstate commerce, and possession of listed species — even captive-bred specimens with valid CITES paperwork. There is no commercial pathway to legally own one in the US. Permits exist for accredited zoos and scientific research, but not for private hobbyists.

This is why you will see Asian arowanas in YouTube fishroom tours from Singapore, Malaysia, Indonesia, the UK, and most of mainland Europe — and almost never from the US. The fish you see in American "monster tank" videos billed as "arowanas" are almost always silver, black, or jardini arowanas, which are different species entirely and fully legal.

Average Size (30+ inches) and Lifespan (20+ years)#

A wild-caught adult Scleropages formosus reaches 35 to 36 inches. In captivity, 28 to 32 inches is more typical, with growth rate heavily dependent on tank size, water quality, and feeding intensity. Juveniles add length fast — a 4-inch juvenile can hit 18 inches inside the first year on heavy feeding, then growth slows to 1-2 inches per year through years three to five.

Lifespan in a properly maintained tank is 15 to 20 years, with verified specimens reaching 25 years and beyond. This is a fish you commit to for the better part of two decades. That timeline matters enormously when you are sizing the tank, planning the filtration, and budgeting the electric bill.

Water Parameters & Tank Requirements#

Asian arowanas are not difficult to keep alive — they are difficult to keep correctly. The species tolerates a wide range of water parameters, but it will not display its full color, develop proper finnage, or avoid skeletal deformities without the right setup. Cutting corners on tank size or filtration shows up in the fish over the course of years, not weeks.

Minimum Tank Size (250+ Gallons for Adults)#

A juvenile Asian arowana under 8 inches can live happily in a 75-gallon tank. By the time it hits 12 inches, the 75 is already cramped. By 18 inches, you need to be in something at the 180-gallon mark or larger. The adult minimum is 250 gallons, with most experienced keepers running 300 gallons or more.

The critical dimension is not volume — it is width and length. An adult arowana needs to turn around without bending its body sharply, and it needs enough horizontal swim path to cruise the surface. A common rule is that the tank width should be at least 1.5 times the length of the fish, and the length should be at least 3 times. For a 30-inch adult, that means a tank measuring at least 90 inches long by 36 inches wide. A 250-gallon tank in standard 96 x 24 x 24 dimensions is functional but tight on width; a 300-gallon 96 x 30 x 24 is the comfortable floor.

Tanks too small or too narrow produce two characteristic deformities: spinal curvature from constant tight turning, and drop eye from the fish constantly looking down for food and reflections off a too-close glass bottom.

Tropical Parameters: 75°F-86°F, pH 6.0-7.0, Soft Water#

Wild Scleropages formosus lives in slow-moving, tannin-stained tributaries of Southeast Asian river systems. The water is warm, soft, and acidic. In captivity, target the following:

The arowana is not as fragile as a wild discus, but it is sensitive to nitrate buildup in ways most large carnivores are not. Chronic nitrate over 30 ppm dulls the red pigmentation in Super Reds and can trigger gill curl, a permanent deformity where the gill covers begin to flare outward.

A blackwater extract or Indian almond leaves in the tank lowers pH gently, adds tannins that mimic the fish's native habitat, and has mild antimicrobial benefits. Many serious arowana keepers run a few leaves in the sump rather than the display tank to avoid the visible tannin staining.

Filtration Needs: High-Turnover Sumps and Nitrate Management#

A 250-gallon tank with a single adult arowana and a few tank mates produces a serious bioload. The fish itself is a messy eater — chunks of shrimp, cricket legs, and pellet dust drift down from the surface during every feeding. Standard hang-on-back or canister filtration will not keep up.

The standard build is a sump at least 25-30% the volume of the display tank (so 60-90 gallons for a 250-gallon main), with three chambers: mechanical (filter socks, replaced weekly), biological (matrix or ceramic media), and a return chamber with the pump and heater. Target 5-7x display tank turnover per hour. For a 250-gallon, that is a return pump rated 1,250-1,750 GPH after head loss.

Because nitrate accumulation is the long-term killer of arowana color and gill health, most serious keepers do 30-50% weekly water changes, period. Automated water change systems with a drain to waste and an auto-fill from a remineralized RO reservoir are common in dedicated arowana setups. Setting up the cycle and filtration on a tank this size is its own project — see our aquarium dimensions guide for footprint planning before you commit to a stand and stand location.

The Importance of a Weighted, Secure Lid#

Asian arowanas evolved to hunt insects and small birds off overhanging branches. They jump. They jump hard. An adult can launch six to eight inches clear of the surface from a standing start, and they will do it from a startled response to a flashlight, a passing pet, or a shadow on the ceiling.

Diet & Feeding#

Asian arowanas are obligate carnivores with a strong surface-feeding instinct. The upturned mouth, the pair of barbels on the lower jaw, and the protrusible jaw mechanism all point to a fish evolved to grab prey from the water surface — insects falling off branches, small fish, occasionally small birds and mammals. Replicating that feeding pattern in captivity matters for both color development and for preventing the specific deformities the species is prone to.

High-Protein Staples: Dubia Roaches, Crickets, and Market Shrimp#

The healthiest captive arowana diet is a varied rotation of whole, high-protein prey items:

• Dubia roaches and crickets: The premium staple. Gut-loaded for 24-48 hours with vegetables and high-quality fish flake before feeding. The chitin provides roughage and the live movement triggers the natural strike response.
• Market shrimp: Frozen raw shrimp from a grocery store, peeled and head-on. A core protein source. Add a vitamin/HUFA supplement weekly to offset the thiaminase content.
• Frozen silversides and smelt: Whole small fish provide complete nutrition. Choose silversides over feeder goldfish — feeders are nutritionally poor and a documented vector for parasites and bacterial infections.
• Mealworms and superworms: Use sparingly. The chitin shell is hard to digest and the fat content is high. A treat, not a staple.
• Floating carnivore pellets: High-quality color-enhancing pellets (Hikari Massivore, NLS Thera+A, JBL NovoBel) form the base of a balanced diet and are easier to vary nutritionally than live prey alone.

Avoid feeder goldfish and rosy reds entirely. The thiaminase in cyprinid feeders breaks down vitamin B1 over time and can cause neurological symptoms in long-lived predators. Feeders are also the single most reliable way to introduce ich, columnaris, and internal parasites into an otherwise clean tank.

Adult feeding frequency is 2-3 times per week, not daily. Juveniles under 8 inches eat once daily; sub-adults from 8-18 inches eat once every other day. Overfed adult arowanas develop fatty livers, drop eye, and shortened lifespans.

Training Juveniles to Accept Floating Pellets#

A juvenile arowana raised exclusively on live prey will refuse pellets as an adult, locking you into a more expensive and disease-prone feeding regime for the next 20 years. The time to convert is when the fish is between 4 and 10 inches, when food imprinting is still flexible.

The standard technique is gradual replacement: start with one feeding per week of pellets only, with the live/frozen prey withheld until the fish accepts the pellets. Once the fish takes pellets readily, increase to alternate feedings. Within four to six weeks, most juveniles will accept pellets as a primary food. Adults that have never seen a pellet are much harder to convert and may need to be hunger-trained over weeks.

Avoiding "Drop Eye": Floating Food vs. Bottom Scavenging#

Drop eye — where one or both eyes droop downward — is the most common and most visible Asian arowana deformity. The cause is debated, but the two leading theories are:

1. Mechanical: The fish constantly looks downward at food that has sunk or at reflections in the tank bottom, and the eye muscles adapt over months and years.
2. Dietary: Excess fat in the diet (especially from feeder fish, mealworms, and oily proteins) deposits behind the eye and pushes the eyeball forward and down.

The prevention strategy addresses both. Feed only at the surface — floating pellets, floating insects, and shrimp held briefly at the surface with feeding tongs. Keep the tank background and substrate dark and matte to reduce downward reflections. Avoid mixing the arowana with bottom-feeding tank mates that draw its attention downward during feeding. Keep dietary fat moderate by leaning on lean proteins (shrimp, dubia roaches) over fatty options (mealworms, fatty feeders).

Drop eye is often considered cosmetic by serious keepers (it does not impair vision or shorten life), but in the high-end arowana market a drop-eyed Super Red can lose 50-70% of its resale value. Prevention is the only treatment — once it develops, it is permanent.

Tank Mates & Compatibility#

The Asian arowana is a top-tier predator, but it is a surface predator with limited interest in fish that stay below mid-water. This makes it surprisingly compatible with certain large, calm species — provided everything in the tank is too big to swallow whole and not aggressive enough to nip the arowana's flowing fins.

Large Bottom Dwellers: Potamotrygon Rays and Polypterus#

The classic "monster tank" pairing is an adult Asian arowana with freshwater stingrays of the genus Potamotrygon — motoro, black diamond, or P14 rays. Rays occupy the substrate, the arowana cruises the surface, and the two species rarely interact. The tank requirements are similar: large footprint, soft acidic water, pristine nitrate management.

Polypterus species (bichirs) are a second strong choice. Senegal bichirs, ornate bichirs, endlicheri bichirs, and delhezi bichirs are slow-moving, prehistoric-looking bottom fish that ignore the arowana entirely. They are messy eaters, so factor that into your filtration math.

A few additional compatible bottom species include large Loricariidae (royal pleco, sailfin pleco, common pleco), and large catfish like the redtail catfish or tiger shovelnose — though redtails grow into 4-foot monsters that need their own enormous tank long-term.

Mid-Water Companions: Datnoids and Large Silver Dollars#

Mid-water tank mates have to thread a needle: large enough not to be eaten, calm enough not to harass the arowana, and not so similar in shape that the arowana reads them as competition. The proven options:

• Datnoids (Indonesian Tigerfish, Siamese Tigerfish): The traditional mid-water companion. Banded yellow and black, calm-tempered, peak around 15-18 inches.
• Clown loaches: A school of 6+ adult clown loaches occupies the lower mid-water and adds activity without threatening the arowana.
• Large silver dollars: A school of 6-8 adult silver dollars provides movement without aggression. They are also useful as algae-eating dither fish that calm the arowana down.
• Geophagus species (eartheaters): Calm large cichlids that work the substrate and ignore the upper water column.
• Tinfoil barbs: Adult tinfoils (10-14 inches) are too big to be eaten and active enough to keep the tank visually busy.

Avoid anything aggressive enough to nip the arowana's pectoral fins or barbels — that rules out most large cichlids (oscars, midas, red devils, jaguars). Avoid anything small enough to fit in the arowana's mouth — that rules out tetras, barbs under 6 inches, and most rasboras.

Managing Intraspecific Aggression (The "Solo King" Mentality)#

Asian arowanas are notoriously aggressive toward other arowanas, including their own species. In the wild, mature adults are solitary and territorial. In captivity, a single arowana per tank is the safest setup.

If you have the space and want to keep multiples, the rule of thumb is 6 or more in a tank of 1,000+ gallons — large enough that no individual can dominate the entire tank, and enough fish that aggression gets distributed across the group. Anything in between (2-5 fish in a normal large tank) almost always ends with one dominant fish killing or maiming the others. The "Solo King" mentality is not metaphor — it is observable behavior within weeks of pairing.

Common Health Issues#

Asian arowanas are robust fish, but they have a handful of species-specific conditions that show up in even well-kept specimens. Most are preventable with the right setup; most are difficult or impossible to reverse once established.

Preventing "Drop Eye" and Protruding Lower Jaws#

Drop eye prevention was covered in the diet section, but the related condition of protruding lower jaw (also called "underbite" or "predator jaw") deserves mention. The lower jaw progressively extends past the upper jaw, eventually impairing the fish's ability to feed. Causes include genetic predisposition, mechanical injury from striking the tank glass during feeding strikes, and chronic feeding from below.

Prevention overlaps heavily with drop eye prevention: surface feeding only, feeding tongs to keep prey in mid-water-or-above, large enough tank that the fish cannot bash the glass during a strike, and avoiding live prey that the arowana has to chase off the substrate.

Treating Gill Curl and Scale Protrusion#

Gill curl is the gradual outward flaring of the operculum (gill cover), exposing the gill filaments. The leading cause is chronically poor water quality — specifically, low dissolved oxygen and high nitrate — over weeks or months. The cosmetic damage is permanent once it develops, but progression can be halted by addressing water quality: increase aeration, drop nitrate to under 10 ppm via larger and more frequent water changes, and add a strong return flow that breaks the surface.

Scale protrusion (raised or lifted scales over part of the body) is usually a secondary symptom of internal bacterial infection or kidney issues, often called "pinecone disease" when it goes systemic. It is serious. Quarantine the fish, raise the temperature to 84°F, and treat with a broad-spectrum antibiotic (kanamycin or a kanamycin/nitrofurazone combination) in a hospital tank. By the time the protrusion is visible, prognosis is guarded.

Stress Management During Water Changes#

A 50% water change on a 250-gallon tank is a substantial environmental shift, and arowanas notice. The two failure modes are temperature shock (cold tap water hitting the tank too fast) and pH shock (city tap water at pH 8 hitting an aged arowana tank at pH 6.5).

The standard approach is to drain to a marked level, refill from a temperature-matched and pre-treated source, and run the refill slowly enough that parameters change gradually over 30+ minutes. Many keepers run a python-style refill from a separate barrel of pre-mixed RO/tap blend, treated with dechlorinator and warmed to within 1°F of the tank.

For tanks of this size, automated drip systems running a continuous 5-10% daily water change keep parameters rock-stable and eliminate the stress event entirely. The capital cost is real but pays for itself in fish health over a 20-year keep.

The US Legal Landscape#

This is the section that decides whether the rest of the guide matters to you. If you are reading from anywhere outside the United States, skip ahead to the cheat sheet.

Why Asian Arowanas are Illegal in the United States (Endangered Species Act)#

The Asian arowana was listed as endangered under the US Endangered Species Act in 1976, four years before the species began being commercially captive-bred in Singapore. The original listing was driven by collapsing wild populations from habitat loss and over-collection for the live aquarium trade. The listing has not been amended since.

Under ESA section 9, it is illegal to:

• Import the species into the US, even with valid CITES paperwork
• Export the species from the US
• Sell or offer for sale the species in interstate or foreign commerce
• Possess any specimen taken in violation of the act

Captive-bred status does not exempt the fish. CITES paperwork from the country of origin does not exempt the fish. The only legal pathway is a Captive-Bred Wildlife (CBW) permit issued by US Fish and Wildlife Service, which is granted to accredited zoos, aquariums, and qualified researchers — never to private hobbyists.

US Fish and Wildlife Service has actively prosecuted Asian arowana smuggling cases, often resulting from undercover Lacey Act stings. Penalties have included fines of $50,000 to $500,000 and federal prison terms of up to several years. The fish themselves, when seized, are typically transferred to USFWS-approved holding facilities or euthanized.

Legal Alternatives for US Hobbyists (Silver, Black, and Jardini Arowanas)#

The good news is that Scleropages formosus is one of several arowana species, and the others are perfectly legal in the US. They differ from the Asian arowana in coloration (none develop the deep red or full gold of the prized Asian strains), but they offer the same dragon-like body, the same surface-cruising behavior, and the same large-tank monster-fish presence.

• Silver arowana (Osteoglossum bicirrhosum): The most popular legal alternative. Native to the Amazon basin. Bright silver scales, blue-green iridescence in good light, and the longest body of any arowana species — adults reach 36-40 inches. Slightly more demanding on water quality than Asian arowanas and notoriously prone to drop eye. Tank requirements are similar (250+ gallons for adults). Widely available at specialty stores for $40-150 as juveniles.
• Black arowana (Osteoglossum ferreirai): The silver arowana's South American cousin. Juveniles are dramatically marked with a yellow stripe and black bars; adults transition to a darker gray-silver with subtle iridescence. Slightly smaller adult size (around 30 inches), slightly higher price tag than silvers.
• Jardini arowana (Scleropages jardinii): Same genus as the Asian arowana, native to northern Australia and southern New Guinea. Smaller (24-28 inches), more aggressive, with a distinctive red-gold spot pattern on each scale. Of the legal alternatives, the jardini is the closest cousin to the Asian arowana in body type and behavior, and the only legal Scleropages in the US.
• Leichardti arowana (Scleropages leichardti): Sometimes called the spotted barramundi. Less common in US trade, more common in Australian and Asian markets. Similar care to the jardini.

For a US hobbyist who wants the dragon fish look, the practical choice is between the silver arowana (most affordable, easiest to source, most peaceful) and the jardini arowana (most similar to a true Asian, more aggressive, harder to find tank mates for).

Quick-Reference Cheat Sheet#

The condensed version, for the bookmark.