Blind Cave Tetra

Blind Cave Tetra (Astyanax mexicanus, cave form)

Appearance & Behavior

Bring a fascinating example of cave adaptation to your freshwater aquarium with Blind Cave Tetras. Their pale, pinkish-white bodies lack the prominent eyes and pigmentation of surface-dwelling relatives. Instead of relying on sight, they locate food and navigate using other senses, including sensitivity to water movement. These active fish explore confidently once settled, but their vigorous feeding and tendency to nip make them better suited to a carefully planned aquarium than a delicate community.

Quick Care Guide

• Care Level: Easy to moderate; careful stocking and feeding management required

• Temperament: Active and potentially nippy; may eat very small tankmates

• Adult Size: Approximately 3–4 inches

• Minimum Aquarium Size: 30 gallons; a 36-inch or longer aquarium recommended for an adult group

• Temperature: 68–77°F

• pH: 6.5–8.0

• Water Hardness: Moderately hard water, approximately 5–20 dGH

• Diet: Omnivore

• Swimming Area: All levels, frequently exploring the middle and bottom

• Recommended Quantity: At least 6 when aquarium space and stocking allow; provide ample room and monitor group interactions

Aquarium Setup & Compatibility

Provide generous open swimming space, smooth rocks or driftwood, and a sand or smooth-gravel substrate. Blind Cave Tetras do best in a fully cycled aquarium with stable water conditions, good oxygenation, and moderate circulation. They do not require complete darkness; subdued lighting can suit a cave-style display, with lighting adjusted to any live plants. Avoid sharp decorations and narrow spaces where fish could become trapped, protect filter intakes, and use a secure lid.

A species-focused aquarium is often the simplest choice. For a community setup, choose robust, similarly sized, short-finned fish with compatible temperature and water requirements. Avoid tiny fish, dwarf shrimp, slow-moving or long-finned fish, and timid bottom dwellers that may be disturbed during foraging. Blindness does not prevent these fish from finding and eating small animals. Watch for persistent chasing, fin damage, or feeding competition, and separate incompatible fish when needed.

Feeding

Feed Hatchery Diet 1.2 mm, supplemented with Daphnia and Bloodworms. Include a quality sinking omnivore food so they can forage naturally. Offer measured, small portions across more than one feeding spot and confirm that each fish is eating. Their enthusiastic searching is not a reason to keep adding food; remove uneaten portions and avoid overfeeding.