Hydrolycus Tatauaia

Datasheet

General Description

Hydrolycus Tatauaia, commonly known as the "Wolf Fish," is a striking species characterized by its silvery body with a dark dorsal surface and distinct reddish to orange fin rays. Belonging to the family Cynodontidae, this predatory fish is notable for its elongate dark blotch behind the opercle and a dark adipose fin with black pigmentation. It can reach a maximum size of 45.5cm and is primarily found in the lower and central Amazon region, as well as in the upper Orinoco basin in Venezuela and Colombia.

Aquarium Setup

The Hydrolycus Tatauaia is best kept in a tank of at least 10000 litres with a bare setup, preferring dim lighting and moderate water movement. It thrives in stable water conditions, requiring a high level of dissolved oxygen. A tightly-fitting cover is essential due to its tendency to jump. Suitable tank mates include non-aggressive fishes of similar size that cannot fit into its mouth, or it can be kept in groups with a minimum of three individuals in a suitably-sized aquarium.

Behaviour

This species is generally peaceful but may show aggression towards similarly shaped or colored fish, particularly in confined spaces. It is known to attack other species if space is limited, making it most suitable when kept alone or with carefully selected tank mates. Hydrolycus Tatauaia is nocturnal to some extent and benefits from a nocturnal feeding schedule.

Feeding and Diet

As an obligate piscivore, the "Wolf Fish" feeds primarily on live fish. Newly imported specimens may only accept live prey initially but can be weaned onto dead alternatives over time. It is advised not to feed mammalian or avian meats, as well as the long-term use of feeder fish due to health risks and lack of nutritional value.

Reproduction & Dimorphism

Reproduction among Hydrolycus Tatauaia occurs between November and April, with adults undergoing upstream migrations for this purpose. While adults are associated with main river channels, juveniles are likely found in smaller tributaries and flooded forest areas. Sexual dimorphism in this species is not distinctly documented.

Habitat and Distribution

Primarily a pelagic species, Hydrolycus Tatauaia inhabits flowing stretches of main river channels and larger tributaries in both white and black water rivers. Its distribution spans the lower and central Amazon region, the upper Orinoco basin in Venezuela and Colombia, as well as coastal drainages in Guyana. The type locality for this species is Rio Xingu, Belo Monte, Brazil.

Etymology

The genus name Hydrolycus is derived from the Greek words "hydro" meaning 'water' and "lykos" meaning 'wolf', likely in reference to the predatory nature and appearance of the species.