The arapaima (Arapaima gigas), or pirarucu as it is known in Brazil, is one of the largest freshwater fishes in the world. Its local name derives from the indigenous words for red and fish, a reference either to the striking red flecks on the scales towards the tail or the reddish-orange colour of the filleted flesh. For its huge size, the arapaima is sleek. In common with other fish belonging to the superorder Osteoglossomorpha (bony-tongued fish), the arapaima has a tongue with sharp, bony teeth that together with teeth on the roof of its palate are involved in disabling and shredding prey.