A versatile species with two forms: a surface-dwelling type and a blind, cave-dwelling form.
Overview
Astyanax mexicanus, commonly known as the Mexican Tetra or Blind Cave Tetra, is a fascinating species with two distinct forms. The surface-dwelling form has eyes and a silvery body, while the cave-dwelling form is eyeless and has a pale, almost translucent appearance. Both are hardy and adaptable, making them popular in the aquarium trade.
Tank Requirements
A tank of at least 100 liters is recommended for a group of 6 or more Mexican Tetras. They thrive in water temperatures between 20–25°C, a pH of 6.5–8.0, and a general hardness of 4–20 dGH. Provide a mix of open swimming spaces and hiding spots such as rocks, driftwood, or plants. For the cave-dwelling variety, subdued lighting and a natural substrate enhance their environment.
Feeding and Diet
These tetras are omnivores and accept a wide variety of foods. Offer a balanced diet of high-quality flakes or pellets, supplemented with live or frozen foods like brine shrimp, bloodworms, and daphnia. For optimal health, include vegetable-based options like spirulina flakes or blanched spinach.
Care and Maintenance
Astyanax mexicanus is a hardy species, tolerant of varying water conditions. Regular water changes and proper filtration are necessary to maintain a clean and stable environment. Their active and social nature makes them ideal for a community tank with other non-aggressive species.
Compatibility
Mexican Tetras are peaceful but active fish, best kept in groups of their own kind to reduce stress. They can coexist with other similarly sized, non-aggressive tankmates such as other tetras, barbs, or peaceful cichlids. Avoid housing them with very small or slow-moving species.
Breeding
Breeding Astyanax mexicanus is relatively straightforward. They are egg scatterers and require a separate breeding tank with fine-leafed plants or a spawning mop. Conditioning the adults with a protein-rich diet can encourage spawning. Remove the adults after eggs are laid to prevent them from eating the eggs. The fry hatch in about 24–36 hours and should be fed infusoria or finely crushed flakes until they are large enough to eat baby brine shrimp.