Can Blind Cave Tetra and Emperor Tetra Live Together?

🟢Ideal Tank Mates

Yes, Blind Cave Tetra and Emperor Tetra are ideal tank mates. Both species share compatible water parameters and peaceful temperaments, making them well-suited for a community aquarium. A minimum tank size of 132 litres is recommended.


At a Glance

Blind Cave Tetra

Astyanax mexicanus

Emperor Tetra

Nematobrycon palmeri

🐟Family Group
Blind Cave Tetra
Characins
Emperor Tetra
Characins
Temperament
Blind Cave Tetra
Mostly Peaceful (4/10)
Emperor Tetra
Peaceful (2/10)
Temperature
✓ Compatible
Blind Cave Tetra
20–25°C
Emperor Tetra
23–27°C
pH Range
✓ Compatible
Blind Cave Tetra
6.5–8
Emperor Tetra
5–7.5
Hardness (dGH)
✓ Compatible
Blind Cave Tetra
8–20
Emperor Tetra
1–12
Water Type
✓ Compatible
Blind Cave Tetra
Freshwater Only
Emperor Tetra
Freshwater Only
Flow Preference
✓ Compatible
Blind Cave Tetra
Moderate
Emperor Tetra
Moderate
Min Tank Volume
Combined: 132 L
Blind Cave Tetra
110 L
Emperor Tetra
75 L
Swimming Level
Shared: 1 zone
Blind Cave Tetra
MiddleBottom
Emperor Tetra
Middle
🏷️Behavior Tags
Blind Cave Tetra
Hyperactive / Fast SwimmerFin NipperAggressive Eater (Starves shy fish)
Emperor Tetra
Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator

Behaviour & Temperament

Blind Cave Tetra is a generally mild-mannered species (4/10), while Emperor Tetra is peaceful (2/10). This modest difference means Blind Cave Tetra may occasionally assert dominance over Emperor Tetra.

Blind Cave Tetra and Emperor Tetra both frequent the Middle (Open Water) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

Worth noting: Emperor Tetra is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 23°C and 25°C. Aim for the midpoint of this range (around 24.0°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 8–12 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Blind Cave Tetra and Emperor Tetra together, plan for an aquarium of at least 132 litres with a minimum length of 80 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

Providing a mix of open swimming space and sheltered areas with rocks, driftwood, or plants will keep both species comfortable and allow natural behaviour.

Specific environmental needs for this combination include: Smooth Gravel (Sensitive Barbels), Plants - Densely covered, Plants - Floating, Leaf Litter/Blackwater. Meeting these requirements will help both species thrive.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

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Frequently Asked Questions

Can Blind Cave Tetra and Emperor Tetra live together?

Yes. Blind Cave Tetra and Emperor Tetra are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.

What size tank do Blind Cave Tetra and Emperor Tetra need?

A minimum of 132 litres (tank length at least 80 cm) is recommended. This provides enough space for both species to establish their own areas and reduces the likelihood of territorial disputes.

What water temperature is best for Blind Cave Tetra and Emperor Tetra together?

Keep the aquarium between 23°C and 25°C. A target of around 24.0°C sits comfortably within both species' preferred ranges.

Are Blind Cave Tetra or Emperor Tetra aggressive?

Blind Cave Tetra is generally mild-mannered (4/10) and Emperor Tetra is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Blind Cave Tetra and Emperor Tetra need?

Both species overlap in the 6.5–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Will Blind Cave Tetra nip Emperor Tetra's fins?

Blind Cave Tetra is a known fin nipper. If Emperor Tetra has long or flowing fins, there is a real risk of fin damage. Keeping Blind Cave Tetra in a larger group can help redirect nipping behaviour toward conspecifics.


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