A fascinating, totally blind species originating from limestone caves in Mexico. They are born with eyes that degenerate as they grow. Navigating via their highly sensitive lateral line, they are extremely active and constantly scavenge for food. Best kept in a species tank or with fast-moving, short-finned fish, as their erratic swimming and feeding style can result in accidental fin-nipping of slow tank mates.
At a Glance
Tank Requirements
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Water Parameters
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Temperament & Compatibility
Available Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Standard (Blind Cave Form)
The common blind, pigment-less form found in the aquarium trade. Despite lacking eyes, they are voracious eaters and highly capable navigators. They require an environment free of sharp decor (like jagged rocks) to prevent injury when they bump into objects.
Same care requirements as the base species
Also known as: Albino Blind Cave, Blind Tetra
Top Tank Mates
Japanese Ricefish (Medaka)
Oryzias latipes
🟢Ideal Tank MatesLemon Tetra
Hyphessobrycon pulchripinnis
🟢Ideal Tank MatesPenguin Tetra
Thayeria boehlkei
🟢Ideal Tank MatesPanda Garra
Garra flavatra
🟢Ideal Tank MatesEmperor Tetra
Nematobrycon palmeri
🟢Ideal Tank MatesNorman's Lampeye Killifish
Poropanchax normani
🟢Ideal Tank MatesBlind Cave Tetra Care Guide Summary
The Blind Cave Tetra, scientifically known as Astyanax mexicanus, belongs to the Characins family group. Adults reach a maximum size of approximately 10 cm and have a compressed body shape with a moderate growth rate. Classified as mostly peaceful, this species primarily occupies the mid-level and bottom zones of the aquarium and produces a low level of biological waste.
To thrive, the Blind Cave Tetra requires a freshwater only aquarium with a minimum volume of 110 litres and a tank length of at least 80 cm. Water temperature should be maintained between 20°C and 25°C, with a pH range of 6.5–8 and a general hardness of 8–20 dGH. A moderate water flow is preferred. An aquarium test kit can help you monitor these values.
The Blind Cave Tetra is a rewarding species to keep, provided its core environmental needs are met. The Blind Cave Tetra is typically available in one standard form.
Blind Cave Tetra Habitat Setup
When setting up an aquarium for the Blind Cave Tetra, a moderate water flow best suits their natural preferences. Because this species occupies the mid-level and bottom zones, the aquarium layout should prioritise open swimming space in the centre of the tank for free movement and sufficient floor space with hiding spots among rocks, wood, or dense planting. Useful additions include smooth gravel or rounded substrate to protect their sensitive barbels. Browse smooth aquarium gravel options to find the best fit.
Blind Cave Tetra Compatibility Notes
Classified as mostly peaceful, the Blind Cave Tetra is a schooling species that feels most secure in a sizeable group, where natural shoaling behaviour reduces stress and brings out their best colours. When choosing tankmates, avoid housing with slow-moving or long-finned species that may become targets for fin nipping, shy or slow-feeding tankmates may be outcompeted at feeding time, and their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the mid-level and bottom zones can help reduce competition and territorial overlap.
Frequently Asked Questions About Blind Cave Tetra
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Similar Species
Glowlight Tetra
Hemigrammus erythrozonus
A peaceful, schooling nano fish native to the Essequibo River basin in South America. They are famous for their translucent bodies and the striking iridescent neon-orange stripe running from snout to tail. They thrive in mature, planted aquariums with slightly soft, acidic water and subdued lighting.
Diamond Tetra
Moenkhausia pittieri
A stunning, deep-bodied tetra endemic to Lake Valencia in Venezuela. Named for the brilliant, iridescent scales on its flanks that sparkle like diamonds under the right lighting. They are highly active, peaceful schooling fish that thrive in well-planted aquariums. Males develop spectacular, flowing fins as they mature.
X-Ray Tetra (Pristella)
Pristella maxillaris
A remarkably hardy and peaceful schooling fish, named for its translucent body that reveals its internal organs. Uniquely among tetras, it naturally inhabits both fresh and slightly brackish coastal waters in South America, making it incredibly adaptable to various aquarium conditions. An excellent choice for beginners.
Cardinal Tetra
Paracheirodon axelrodi
A stunning schooling fish native to the upper Orinoco and Rio Negro basins in South America. Famous for its brilliant iridescent blue line and a vivid red stripe that extends the full length of its body (distinguishing it from the Neon Tetra). They are strictly schooling fish that thrive in warm, acidic blackwater environments.
Lemon Tetra
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A peaceful, deep-bodied schooling tetra known for its translucent yellow coloration and striking black and yellow fins. They are robust and active, making them an excellent choice for planted community aquariums. Their colors intensify significantly in a well-established tank with a dark substrate and proper schooling numbers.
Congo Tetra
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A stunning, large schooling fish native to the Congo River basin. Known for their iridescent rainbow colors and active swimming behavior. Despite their size, they are notoriously peaceful and can be skittish, requiring ample swimming space, dim lighting or floating plants, and peaceful tank mates. Avoid keeping with fin-nippers.