Hoplias
General description
Hoplias are large fish that can grow up to 75 cm in length and weigh more than 6 kg. Their body is robust, cylindrical and elongated. The mouth is wide and anterior with jaws armed with large canine teeth; They have small teeth on the palate. They lack an adipose fin. The tail fin is rounded. The body is brown or greenish with outlined dark spots horizontally in the midline, the fins are greenish brown with small black spots.
The genus has 13 described species:
1. Hoplias aimara (Valenciennes, 1847)
2. Hoplias australis Oyakawa & Mattox, 2009
3. Hoplias brasiliensis (Spix & Agassiz, 1829)
4. Hoplias curupira Oyakawa & Mattox, 2009 Black wolf-fish
5. Hoplias intermedius (Günther, 1864)
6. Hoplias lacerdae Miranda Ribeiro, 1908
7. Hoplias macrophthalmus (Pellegrin, 1907) Giant trahira
8. Hoplias malabaricus (Bloch, 1794) Trahira
9. Hoplias mbigua Azpelicueta, Benítez, Aichino & Mendez, 2015
10. Hoplias microcephalus (Agassiz, 1829)
11. Hoplias microlepis (Günther, 1864)
12. Hoplias patana (Valenciennes, 1847)
13. Hoplias teres (Valenciennes, 1847)
Species and distribution in Uruguay
In Uruguay there are four species of this genus. Hoplias lacerdae, distributed in the del Plata basin; H. argentinensis, probably distributed throughout the country; H. australis, recorded in some places in the Uruguay basin; H. see. missionera, distributed in the Uruguay River basin.
Diet
Top predators of aquatic ecosystems; They feed on plankton in their first days of life, when they are young. They start feeding on insects and crustaceans and the adults also feed on mollusks, fish and other vertebrates such as amphibians and
small mammals and birds.
Reproduction
They reproduce in the spring. They build a nest in water with little current and depth, where the eggs are deposited and the male is responsible for aggressively caring for them until they hatch.
Habitat
They are found in lagoons, streams and rivers; juveniles can also be found in wetlands. Hoplias lacerdae prefers habitats with water movement, while H. argentinensis prefers standing water. They are generally solitary fish. They rarely form schools.
Conservation
Its conservation status has not been evaluated by IUCN. They are all included in the list of priority species for conservation in the SNAP program.
Additional comments. Hoplias argentinensis is one of the most important species in artisanal and recreational freshwater fisheries in Uruguay.
Key references. Oyakawa & Mattox, 2009; Rosso et al. (2016, 2018).
CC BY-NC-SA: Loureiro M, González-Bergonzoni I, Teixeira de
Mello F. 2023. Peces de Agua Dulce de Uruguay. Segunda Edición.
Laboratorio Zoologia de Vertebrados, Facultad de Ciencias, Universidad
de la República.
