Osteoglossids are carnivorous, often being specialized surface feeders. They are excellent jumpers; it has been reported that

Osteoglossum species have been seen leaping more than 6 feet (almost 2 metres) from the water surface to pick off

insects and birds from overhanging branches in South America, hence the nickname "water monkeys". Arowanas have

been rumored to capture prey as large as low flying bats and small birds. All species are large, and the arapaima is one of the

world's largest freshwater fish, at 2.5 metres (8.2 ft) in length. Arowana typically grow to around 3 to 4 feet in captivity.

Several species of osteoglossid exhibit extensive parental care. They build nests and protect the young after they hatch.

Some species are mouthbrooders, the parents holding sometimes hundreds of eggs in their mouths. The young may make

several tentative trips outside the parent's mouth to investigate the surroundings before leaving permanently.