Arowana

The arowana refers to species in the genus Osteoglossum (family Osteoglossidae, the "bonytongues"), large freshwater fish native to the Amazon and Orinoco river basins of South America, with the silver arowana (Osteoglossum bicirrhosum) as the most widely known representative. Bonytongues are among the most ancient surviving groups of bony fish, with fossil relatives dating back over 100 million years. Arowanas are popular ornamental fish in the aquarium trade and are notable for their striking ability to leap out of the water to capture insects and small animals from overhanging vegetation.

Arowanas display a distinctive combination of features:

• Elongated, laterally flattened, silvery body
• Large, upturned mouth with two fleshy barbels on the lower jaw
• Long, low dorsal and anal fins that extend back nearly to the tail
• Large, coin-like metallic scales
• An upward-angled head profile suited to surface feeding Its slender, silvery build and paired chin barbels distinguish it from the much bulkier, differently colored arapaima, another large bonytongue found in the same rivers. Its close relative, the black arowana (Osteoglossum ferreirai), looks similar but shows darker fin edging as a juvenile.

Arowanas inhabit slow-moving blackwater rivers, floodplain lakes, and flooded forest margins throughout the Amazon and Orinoco river basins of South America. They are typically found near the water's surface, close to overhanging vegetation and submerged structure that provides cover and access to terrestrial prey. Warm, tropical freshwater with dense riparian vegetation along the banks characterizes their preferred habitat, and seasonal flooding expands available territory during high-water periods. During dry-season low water, they retreat into deeper main river channels until the floodplain refills.

Arowanas are surface-oriented ambush predators renowned for leaping well clear of the water to snatch insects, small birds, and other prey from low-hanging branches. Reproduction involves mouthbrooding, in which the male carries fertilized eggs and subsequently the hatched fry inside his mouth for protection until they are able to fend for themselves. They are generally solitary or loosely associated with other individuals, holding informal territories near favored feeding areas along the water's surface.