Retroculus lapidifer is a species of cichlid native to tropical South America, where it is found in the rivers of the southeastern Amazon basin in Brazil.

It resembles a marine snapper (genus Lutjanus) in body shape and has five distinctive dark vertical bars on each side.

[7] The swim bladder is reduced in size in this fish and it spends much of its time hopping around and perching on the riverbed, propped up by its pelvic fins, in the manner of a goby.

During feeding, it repeatedly dives head first into the sediment with its mouth open wide, and then expels sand through its gill chambers.

Adult fish have been observed carrying small pebbles in their mouths to build the nest, hence the specific name lapidifer (bearer of stones).