Clown featherback
(Chitala ornata)

The clown featherback, clown knifefish, or spotted knifefish, Chitala ornata, is a nocturnal tropical fish with a long, knife-like body. This knifefish is native to freshwater habitats in Cambodia, Laos, Thailand, and Vietnam, but it has also been introduced to regions outside its native range. It is one of the worlds most invasive species.

This species is native to Cambodia, Laos, Thailand, and Vietnam, where found in the Mekong, Chao Phraya, and Meklong River basins. It has also been introduced to regions outside its native range, including the Philippines, Indonesia, Myanmar, Singapore, Sri Lanka, Malaysia and Palm Beach County, Florida, United States. It has either spread to or was introduced to Broward County, Florida.

The clown knifefish is very distinct, with normally silvery gray with a long, knife-like body (laterally compressed) and a long anal fin that gives it its common name. Mature fish normally have five to 10 (or even more) black spots ringed with white that usually decrease in size as the fish grows. These ocellated spots and the lack of faint stripes on the back separate it from Chitala chitala; a species with which it frequently has been confused. Albinos and leucistic specimens are seen with some frequency in the aquarium trade.

Juveniles lack the spots, but are overall striped. Their long anal fins are used to make graceful forward and backward movements.

The clown knifefish grows to a fairly large size, up to 1 m (3.3 ft) and 5 kg (11 lb) in the wild.

It has two nasal tentacles above its large, toothed mouth. In the center of the body is a flag-like dorsal fin and has no ventral fins.