Acanthicus hystrix, the lyre-tail pleco,[4] is a species of armored catfish native to the Amazon, Tocantins–Araguaia and Orinoco basins.

[4] The species is occasionally seen in the aquarium trade, but its adult size and territorially aggressive behavior means that a very large tank is required.

[4] Its color ranges from medium-brown to near-black (especially those from the Madeira, Branco and Xingu rivers are dark), and the underparts often have a vermiculated pattern.

[2] Some of the variants are commonly considered as separate, undescribed species in the aquarium trade (e.g., L193 from the Orinoco basin and L407 from the Branco basin; in the L-number system), but there is extensive overlap in the morphometrics of the different populations.

[2] Unlike the polka dot lyre-tail pleco (A. adonis), A. hystrix never has white spots.