Asian Arowana

Adults can reach a length of 90 cm. The fish has an elongated body with large pectoral fins. The dorsal and anal fins are set close to the tail. Its caudal fin is noticeably larger than that of the silver arowana from South America. Another striking feature is the size of the scales, each of which can be up to 2 cm across. Colouration varies widely and depends on geographic origin: green, silver, golden and red forms are recognised, the last two being the most highly prized.

If the various geographic forms are taken into account, the natural range of the Asian arowana extends throughout South-East Asia, including the archipelagos of Indonesia and Malaysia. In the wild these fish inhabit marshy still waters and river backwaters, preferring to stay in shaded areas near the bank, among flooded tropical forest.

These fish live mainly in the upper layers of the water. During daylight hours they prefer to take cover beneath vegetation overhanging the surface, and among submerged driftwood and roots. They are most active in the evening and at night, when they come out to hunt. Asian arowanas are predatory and territorial, competing with one another for food. As a rule they are kept singly, or in company with large bottom-dwelling species or with fish that occupy the middle of the water column.

The Asian arowana is not a fish for beginners. Those who decide to acquire one are likely to have a thorough knowledge of its requirements already, and can afford advice from qualified specialists. For that reason this site will not dwell on the finer points of its care and will confine itself to the essentials. One Asian arowana needs an aquarium of at least 1000 litres. Since these fish are able to leap out of the water, the tank must have a secure lid. Simplicity matters in the decor — the main thing is to leave plenty of open swimming space in the upper layers. A few large vertical pieces of driftwood are also recommended. The ideal environment for an arowana is clean, soft, acidic water enriched with tannins. Tannins can be introduced with prepared extracts added to the filtration system, or through natural decor such as bark and the leaves of certain plants.

A properly chosen diet is the foundation of successful long-term care for the Asian arowana. Live foods play the key role: shrimp, crickets, mealworms, feeder fish, small amphibians, earthworms, insect larvae and so on. Specialist farms often combine several kinds of food, including dry pelleted feeds. They must not be fed mammalian or avian meat: the lipids it contains cannot be properly metabolised by the fish and lead to excess fat deposits and even organ degeneration.

The Asian arowana is a territorial species that broods its eggs in the mouth, a task performed by the male. In the wild spawning is seasonal; in an aquarium it can be triggered by stable water parameters and a complete diet. Courtship is lengthy and involves the pair circling and swimming together. The female lays a small number of large orange-red eggs, which the male gathers into his mouth. Incubation lasts about 7–8 weeks, until the yolk sac is fully absorbed, after which the fry become independent.

The species is sensitive to water quality and to abrupt changes in conditions, which often trigger bacterial infections and swim bladder problems. Typical ailments include cloudy eye, rot of the fins and gill covers, and ectoparasitic diseases such as anchor worm infestation or ich. Prevention involves maintaining high biological cleanliness, powerful filtration and the elimination of stress factors. Injuries often occur when the fish, being skittish, strikes the aquarium walls or attempts to jump out.

When choosing a specimen, pay attention to the fish's general activity and the cleanliness of its skin. A healthy individual should be inquisitive, with even, tightly seated scales and clear eyes showing no cloudiness or swelling. Avoid specimens with damaged barbels, signs of deformed gill covers, or unnatural behaviour such as constantly staying at the bottom or at the surface. Make sure there are no visible parasites and ask about feeding in the shop to judge the fish's appetite.