The Mexican tetra is a schooling fish (6), which can form schools of up to several hundred or even thousands of individuals (5). It is primarily a carnivorous fish, feeding on aquatic insects, crustaceans, worms, snails and smaller fish (2) (5), but it is also reported to feed on plant matter and algae (5). In Texas, breeding activity has been observed in the surface-dwelling form from late April until September, although elsewhere, such as the lower reaches of the Rio Grande River, reproduction is said to occur year-round. Spawning taking place in late spring and early summer, when a mass of sticky eggs is released into the surrounding waters (5). Mexican tetras develop quickly, which relates to their short lifespan. Those that are born in the spring reproduce for the first time in autumn, and few live for longer than two years (5). Threats
The Mexican tetra is not believed to be in danger of extinction (5). However, a lack of clarification on the taxonomy of Astyanax
species (8) makes it hard to determine the status of this fish and what threats it may face. The cave form has been captured for aquariums, although it is easily bred in captivity and so it is thought that most Mexican tetras sold today are captive bred, thus this trade will not impact wild populations (9).