African Arowana Care Guide - Aquarium Notes, Feeding & Breeding

Despite its common name, Heterotis niloticus is not one of the true Asian or South American arowanas. It is a large African osteoglossiform, more closely associated with the bonytongue group, and has a deep-bodied shape, large scales and a broad, slightly upturned mouth. Its subdued grey-brown to olive colouring helps it blend into muddy, plant-filled waters.

This species is an impressive predator and opportunistic feeder. Young fish are comparatively streamlined, while adults develop a heavier body and can become remarkably powerful swimmers. The mouth is well suited to taking insects, crustaceans, small fish and other food from the water column and surface.

African Arowanas are generally deliberate rather than constantly active, but they can move with surprising speed when feeding or startled. They may show territorial behaviour, particularly in confined surroundings, and their size makes them unsuitable for ordinary community aquariums.

In the wild, they are associated with warm, slow-flowing waters rich in submerged plants, roots and organic cover. They are also notable for their ability to tolerate poorly oxygenated conditions by using a specialised respiratory system, although this should not be taken as a substitute for clean, well-maintained aquarium water.

The African Arowana is native to tropical freshwater habitats across much of sub-Saharan Africa, including the Nile, Niger, Senegal, Volta and Congo drainage systems. It inhabits slow-moving rivers, floodplains, swamps, lakes and seasonal wetlands.

This species needs a massive, mature aquarium or indoor pond of at least 2,000 litres for a single adult, with substantially more space preferred as it grows. A practical adult enclosure should be around 300 cm long, 100 cm wide and 100 cm high or larger, providing a broad uninterrupted swimming area rather than simply extra height. Use a tightly secured cover, strong filtration, efficient aeration and sturdy equipment, with subdued lighting, open water, smooth sand or fine gravel and robust roots or plants arranged around the edges. Leave ample surface clearance and avoid sharp decorations that could damage the fish.

Up to about 100 cm (39 in) in length; females are often somewhat larger and deeper-bodied than males, although individual size varies.

Offer a varied carnivorous and omnivorous diet based on quality large predator pellets, supplemented with earthworms, insects, prawns, mussels and appropriately sized fish foods. Juveniles benefit from smaller offerings and may accept frozen foods readily. Avoid relying on feeder fish, and remove uneaten food promptly because large meals can place a heavy load on water quality.

African Arowanas are best kept alone unless the aquarium is exceptionally large and a compatible group or pair has been carefully established. They will eat small fish, shrimp and other creatures that fit in their mouths, and may injure slow, delicate or surface-dwelling tankmates. Potential companions in a public-sized exhibit include large, robust peaceful fish with similar water requirements, but aggressive cichlids, fin-nippers and other highly territorial species should be avoided.

African Arowanas are rarely bred in home aquariums. In nature, a pair prepares a nest among dense aquatic vegetation, where spawning takes place and the adults guard the eggs and young. Successful breeding requires a very large, mature setup, excellent water quality, compatible adults and seasonal changes in water level and temperature; reliable captive spawning is uncommon.

Sexual differences are subtle. Mature females are generally larger and more robust, while males may be slightly slimmer, making reliable sexing difficult without observing breeding behaviour or examining mature fish closely.