Mexican Tetra

Overview

Mexican Tetra (Astyanax mexicanus) is a middle swimmer for aquariums where the layout leaves enough open swimming space and the water stays stable.

Use these values as planning checks, then make sure the aquarium still has room for behavior, group needs, and calm community fish.

Care requirements

With a Beginner – Intermediate care level, Mexican Tetra is approachable, but it still needs stable water, clean substrate, and a well-planned stocking group.

Because it uses the middle part of the aquarium, leave enough open swimming space instead of crowding that part of the aquarium.

With a lifespan of up to 5 years, this is a fish to plan for long term rather than an impulse addition.

Aquarium size and space needs

An aquarium of 120 L or larger can be a reasonable starting point, but it should not be read as permission to overstock.

At up to 12 cm, Mexican Tetra stays small, but it still needs room to move, feed, and avoid constant competition.

Uses the middle part of the aquarium, so leave enough open swimming space for movement and feeding.

Water parameters

The temperature range for this fish is 20 to 25 °C, which fits many tropical freshwater aquariums. Choose other fish with overlapping temperature needs.

The pH range for this fish is 6.5 to 8. That points to a broad freshwater range, but stability is more important than sudden corrections.

The GH range for this fish is 5 to 30 dGH. That gives some flexibility, but sudden changes are usually more stressful than a stable value that is slightly imperfect.

Temperament and compatibility

As a peaceful middle swimmer, Mexican Tetra is best kept with calm species that will not harass it or dominate the feeding area.

Because this fish uses the middle part of the aquarium, compatibility is easier when other fish are not all competing for the same swimming space.

Swimming zone and behavior

This fish uses the middle part of the aquarium, so leave enough open swimming space for movement and feeding.

Feeding

As an omnivore, Mexican Tetra should receive a varied diet rather than one repeated food type.

Natural habitat and origin

This profile currently lists the origin as Mexico United States. Treat this as a broad regional note rather than a complete habitat description.

Before adding this fish

Use this checklist before treating the profile as a match for an existing aquarium.

• Plan for an aquarium of 120 L or larger.
• Choose other fish with overlapping temperature needs.
• Keep pH stable within the listed range instead of making sudden corrections.
• Avoid aggressive or highly competitive fish.
• Offer a varied diet that matches this species.