Blind Cave Tetra

Astyanax mexicanus

Animalia›Chordata›Actinopterygii›Characidae

📍 Cave systems, Mexico

Eyeless cave-dwelling form of the Mexican tetra. Navigates entirely by lateral line. Surprisingly active and hardy — a fascinating conversation piece in any community tank.

Size3.5"

Min Tank20g

School6+

peaceful

Zonemid

Care Guide

Diet

Blind Cave Tetras are omnivorous and should be fed high-quality flake food, micro pellets, and small frozen foods like brine shrimp or daphnia once daily in small portions. They will also consume algae wafers and vegetable matter. Vary their diet regularly to ensure balanced nutrition and maintain their surprisingly robust health.

Behavior

These fish are surprisingly active despite their lack of eyes, navigating efficiently using their lateral line system. They are peaceful schooling fish that should always be kept in groups of at least 6 to reduce stress and encourage natural behavior. They are most active during feeding times and will interact with tank mates without aggression.

Breeding

Breeding Blind Cave Tetras in captivity is possible but uncommon in home aquariums. They require slightly cooler water (around 20-22°C), dense vegetation or spawning mops, and excellent water quality to trigger spawning. Fry are tiny and require infusoria or liquid fry food initially; remove parents after spawning as they may eat eggs.

Tank Mates

Neon Tetra

Similar size, peaceful temperament, and identical water parameter requirements make them ideal companions

excellent

Otocinclus

Small, peaceful algae eaters that thrive in similar conditions and won't compete for food

excellent

Rummy Nose Tetra

Compatible schooling fish with matching water requirements and peaceful behavior

good

Red Cherry Shrimp

Small invertebrates that occupy different ecological niches; ensure adequate hiding places for shrimp

good

Common Diseases

Ich (Ichthyophthirius multifiliis)

Symptoms

White spots on body and fins, rapid breathing, lethargy, rubbing against objects

Treatment

Raise temperature gradually to 28-30°C, perform daily 25% water changes, use aquarium salt (1 teaspoon per 5 gallons) or commercial ich medication for 7-10 days

Fin Rot

Symptoms

Frayed or deteriorating fins, discoloration at fin edges, lethargy

Treatment

Improve water quality with frequent water changes, remove any sharp tank decorations, treat with antibacterial medication if severe; ensure good filtration

Columnaris (Flexibacter columnaris)

Symptoms

White or grayish film on body, mouth rot, fin damage, loss of appetite

Treatment

Increase water changes to 50% daily, raise temperature to 28°C, treat with antibacterial medication; isolate affected fish if possible

Bloat

Symptoms

Swollen abdomen, loss of appetite, lethargy, difficulty swimming

Treatment

Perform 25% water change, fast the fish for 2-3 days, feed high-quality foods with fiber; treat with antiparasitic medication if parasites are suspected