Banded Tetra, Astyanax aeneus
The Banded Tetra, Astyanax aeneus, whose common Spanish name is pepesca, is a member of the Tetra or Characidae Family, known collectively as pepescas and sardinitas in Mexico. Globally, there are 147 species in the genus Astyanax (named after Astyanax, the son of Hector of Troy in Greek mythology – not to be confused with Helen), of which three are found in the freshwater systems of mainland Mexico.
The Banded Tetras have fusiform bodies with a depth that is 30% to 34% of standard length. They are very colorful being greenish-brown dorsally and transitioning to silver then to white ventrally. Their colors vary from location to location with more brightly colored fish being found in murky environments. The key to identification is the presence of a black rhomboidal blotch on their caudal peduncle that extends to the center of their caudal fin. They have transparent fins with minimal dark red pigments on the first rays of their anal and dorsal fins. Their caudal fin is deeply forked and is either red or yellow. Their head has a small slightly upturned terminal mouth and large eyes placed directly behind the mouth. They are covered with large scales.
The Banded Tetras are a benthopelagic schooling species found in all types of freshwater environments from fast flowing rivers and streams to marshes and stagnant pools. They are found from sea level to elevations of 3,300 feet. They feed on algae, seeds, leaves, aquatic and terrestrial insects, and fish fry. They are a poorly studied species and very little is known about their behavioral patterns.
The Banded Tetras are native to the freshwater systems of southeast and southwest mainland Mexico including the Champotón, Colima, and Papaloapan Rivers.
Due to its prominent black tail blotch, the Banded Tetra is straightforward to identify and cannot be confused with any other species.
The Banded Tetras are very abundant in many locations. They have not been evaluated from a conservation perspective but should be considered of Least Concern. They are caught in abundance via nets in lake shallows and used as bait fish, for food, by the aquarium trade, and for monitoring aquatic environmental quality in areas that have significant pollution from agrochemical residues. They are also an important contributor to their aquatic ecosystems as they excrete disproportionately large amounts of phosphorous, with levels ten-fold higher than other species in the same environment.
Banded Tetra, Astyanax aeneus, Female. Fish caught from Barton Creek, Belize, October 2012. Length: 12 cm (4.7 inches). Catch, photo, and identification courtesy of Josh Leisen (lifelistfishing.com), Gaylord, MI.