Mexican tetra — cave morph

Astyanax mexicanus

An eyeless, pale cave form.

A cave form with pale pink-white skin and reduced eyes.

Adult length: About 7.5 cm
Water temperature: 20–25 °C
Lifespan: Up to 9.8 years
pH: 6.5–8
Hardness: 5–25 dGH

Natural habitat: Inhabits pools, backwaters and springs in creek and river systems, over rocky and sandy beds.

Searching for food may lead to nipping or contact with companions. Avoid very timid or sluggish companions and monitor feeding; blindness does not remove space or water-quality needs.

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Appearance and identification

An eyeless fish is not simply a red-eyed albino.

Same-species behaviour

Keep at least four; cave forms need not school like surface fish.

Space requirements

An 80 × 30 cm base; adjust for group behaviour and swimming room.

Diet and feeding

Offer dry foods and small frozen or live foods. Check that it finds food, and watch for accidental contact with companions.

Compatibility limits

Consider feeding competition, activity and contact nipping individually.

Aquarium environment

Plants may be used as scenery.

Sources

www.fishbase.se ↗ 2026-10-25

www.seriouslyfish.com ↗ 2026-10-23

pmc.ncbi.nlm.nih.gov ↗ 2026-10-23