A Cuiu-Cuiu, a prehistoric-looking catfish found in the Orinoco and surrounding rivers of the Amazon. The Cuiu-Cuiu can grow to 3 feet in length and weigh over 40 pounds. It has scutes along the back half of its body that give support to the tail fin; these give the Cuiu-Cuiu an armored appearance, common in ancient fish.
The ripsaw catfish (Oxydoras niger) or cuiu cuiu is a species of thorny catfish native to the Amazon, Essequibo and São Francisco basins in Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru and Venezuela. This species grows to a length of 100 centimetres (39 in) SL and weights up to 13 kilograms (29 lb). This species is a minor component of local commercial fisheries.[1] Has lateral thorns that can damage a potential predator or handler. It feeds by shifting through sand and detecting eatable parts with the taste receptors in the roof and floor of his mouth.