The Asian Arowana or Scleropages formosus is one of those unique fish that is quite alluring and considered by many as the pinnacle of freshwater fishes. This is due to its regal and somewhat distinguished looks and mannerisms. It is not however a fish meant for everyone and there are a lot of things one needs to know before even thinking about getting this fish. It does not belong in the echelon of general fish and needs some very specific conditions and care to thrive. Let us explore everything there is to know about this fish.

Natural habitat:

The name is a dead giveaway. This fish inhabits the rather murky waters of slow-moving waters around wetlands and swamps of Southeast Asia. Its natural habitats include the Mekong river system in Vietnam and Cambodia, eastern Thailand, Peninsular Malaysia, and the northern Sunda Islands in Sumatra and Borneo. The waters it inhabits is full of tannins and visibility is usually less than a few feet. It spends almost all of its time patrolling just under the surface of the water. It has been introduced to waters around the world sometimes advertently and inadvertently. It should be noted that this fish is endangered in the wild and every effort should be made to get a captive-bred specimen.

Physical Description:

The first clue that this isn’t your typical freshwater fish is the way in which it looks. Let us get this out of the way at the beginning itself. This fish can grow very large. Its maximum length is estimated to be 90 cm or 35 inches but it will most certainly attain 60 cm or 24 inches in a home setup. This coupled with its active swimming nature means that it needs a large tank. The Asian Arowana has the typical build and gait of a predator. They have long bodies and quite prominent fins located towards the back of the body. It has an oblique mouth with a wide gape and there are two barbels at the tip of its mouth. They have multiple teeth inside their mouth including on their tongue. They possess different colorations such as silver, green, red, and gold depending on the particular variety. They have really large scales for their size as well.


This is a finely tuned hunting machine and owing to its larger size can be quite aggressive especially around other smaller fish. They can be fairly aggressive towards other Arowanas as well. In its natural habitat, it prefers swimming under the cover of floating plants and roots and hunting at night. This can make them quite skittish and they can charge from one end of the tank to the other at breakneck speeds. They are fairly strong jumpers as well and are reported to be able to jump to a height of up to 4 meters or 13 feet. They should always be kept in areas where there is relatively low movement around the aquarium. The aquarium should be properly covered. It can be kept with other aggressive fish as long as they do not occupy the top one-third of the water column. They should be kept alone or in groups of at least 4 or more. This dissipates the aggression somewhat and stops any one fish from being constantly bullied. Having said that, Asian Arowanas are highly personable fishes and each has its own character and reaction to other Arowanas.


The Asian Arowana is a relatively hardy fish but due to its size, temperament and dietary requirements it can be difficult to take care of one. Read on to know if the Asian Arowana is your cup of tea.

  • Aquarium size and substrate: They are quite small as juveniles but can grow quite quickly. Juveniles can be kept in a 60 gallon aquarium but within a period of six to eight months they will need an aquarium that is at least 250 gallons for a single Asian Arowana. Adding other fish will need an even larger aquarium. Substrate really doesn’t matter for them as they rarely spend any time near it. An easy to clean option or even a bare-bottom tank is sufficient for keeping Arowanas. The tank’s dimension should be such that the tank is wide enough to allow the rather long fish to move about freely back and forth instead of just side to side.
  • Water conditions: They are a fairly hardy fish but can become sick when the water quality becomes poor. Strong filtration and stable water parameters are necessary. They can be acclimated to a relatively wide range of water conditions. The recommended water parameters are temperatures between 75 °F to 82 °F or 24 °C to 28 °C, pH of between 6.5 and 7.5 and soft to moderately hard water. The Ammonia and Nitrite levels should be zero while the nitrates should be kept under check with weekly water changes.
  • Lighting and tank setup: Really bright light can make the Asian Arowanas skittish and nervous. It can also wash out their colors. It is best to keep the light subdued as it will have the double benefit of keeping the fish calm and comfortable while also bringing out its colors. The tank should be kept as sparse as possible. These Arowanas do not care for tank decoration. In fact, they can get hurt on sharp ornaments. The ideal tank should be bare though a couple of rocks and pebbles can be added to improve the décor. Plants can get uprooted and generally not a good match for the Asian Arowana.
  • Tankmates: This is a tricky thing when it comes to Asian Arowanas. They can go through phases where sometimes they can be accepting of other fish while other times they can be aggressive. The trick is to house them with fish that won’t bother the Arowana and will stay mostly towards the middle or bottom of the tank. Catfish and Plecos are great options and so are Oscars and Green Terrors. Do not keep any fish that are small or slow-moving as the Arowana can take a bite. Its jaws can do some real damage. Keep multiple Arowanas only if the tank has a capacity of at least 800 to 1000 gallons. Even then they could end up in a death match.
  • Diet: Being a predator, they do well on a high-protein diet. Feeder fish should be provided every once in a while to keep them happy but captive-bred Arowanas will readily accept frozen food as well. Earthworms and other critters can be offered too provided it comes from a reliable source. Pellets and flakes are largely ignored by these fish and that is something you have to keep in mind before deciding to buy one. Juveniles can be very fussy and will only accept live food. With time though, they too can be made to accept frozen food.
  • Breeding: This is one fish that is almost impossible to breed in the home aquarium setup. Very few people have managed to successfully breed them at home and even then, they have had the luxury of a very large aquarium or pond. Commercially, these fish are bred in large ponds and trying to breed them for the everyday hobbyist is not feasible.

The Asian Arowana is a great fish but it comes with its challenges mostly due to its space requirements and dietary preferences. However, if you can meet these and maintain a good water quality then this is one fish that can provide a lot of entertainment and fun moments for as long as 10 to 15 years.