Plecos are tropical American fish, of the family Loricariidae, popular in aquaria for their ability to clean tanks by eating algae growth.
Ancistrus species show all the typical features of the Loricariidae. ... In comparison with a typical loricariid (pleco), a bristlenose is typically shorter (4–6 inches or 15 cm or less), more flattened and fatter with a comparatively wider head. Colouration is typically mottled brown, grey or black.
Ancistrus is a genus of nocturnal freshwater fish in the family Loricariidae, native to freshwater habitats in South American and Panama. Fish of this genus are common in the aquarium trade where they are known as bushynose or bristlenose catfish. In the aquarium hobby they are often referred to as bushynose or bristlenose plecos instead, but this may lead to confusion as "pleco" usually is used for Hypostomus Plecostomus and its allies