Ancistrus ranunculus

Ancistrus ranunculus is a species of catfish in the family Loricariidae. It is native to South America, where it occurs in the basins of the Xingu River, Trombetas River and the Tocantins River in Brazil. It inhabits areas with clear water and without strong currents, and it is known to inhabit narrow cracks in submerged rocks, small passages, and spaces below flat rocks. The species is large for a member of Ancistrus, reaching 19.5 cm in total length. It sometimes appears in the aquarium trade, where it is one of several species known as a medusa pleco, although it may be referred to by its L-number, L034.

Etymology
The specific name does not relate to buttercups of the Ranunculus species, instead it is the diminutive of rana, frog, alluding to name Tadpole Ancistrus sometimes given in the aquarium trade, referring to its body shape.