Can Blind Cave Tetra and Gertrude's Spotted Blue-eye Live Together?

🟢Ideal Tank Mates

Yes, Blind Cave Tetra and Gertrude's Spotted Blue-eye 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

Gertrude's Spotted Blue-eye

Pseudomugil gertrudae

🐠Family Group
Blind Cave Tetra
Characins
Gertrude's Spotted Blue-eye
Rainbowfish
Temperament
Blind Cave Tetra
Mostly Peaceful (4/10)
Gertrude's Spotted Blue-eye
Peaceful (2/10)
Temperature
✓ Compatible
Blind Cave Tetra
20–25°C
Gertrude's Spotted Blue-eye
21–28°C
pH Range
✓ Compatible
Blind Cave Tetra
6.5–8
Gertrude's Spotted Blue-eye
6–7.5
Hardness (dGH)
✓ Compatible
Blind Cave Tetra
8–20
Gertrude's Spotted Blue-eye
5–15
Water Type
✓ Compatible
Blind Cave Tetra
Freshwater Only
Gertrude's Spotted Blue-eye
Freshwater Only
Flow Preference
✓ Compatible
Blind Cave Tetra
Moderate
Gertrude's Spotted Blue-eye
Moderate
Min Tank Volume
Combined: 132 L
Blind Cave Tetra
110 L
Gertrude's Spotted Blue-eye
38 L
Swimming Level
Shared: 1 zone
Blind Cave Tetra
MiddleBottom
Gertrude's Spotted Blue-eye
TopMiddle
🏷️Behavior Tags
Blind Cave Tetra
Hyperactive / Fast SwimmerFin NipperAggressive Eater (Starves shy fish)
Gertrude's Spotted Blue-eye
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator

Behaviour & Temperament

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

Blind Cave Tetra and Gertrude's Spotted Blue-eye 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: Gertrude's Spotted Blue-eye is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 21°C and 25°C. Aim for the midpoint of this range (around 23.0°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 8–15 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 Gertrude's Spotted Blue-eye 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.

Find the right tank equipment

Browse tanks, décor, and equipment suited for this setup.

Frequently Asked Questions

Can Blind Cave Tetra and Gertrude's Spotted Blue-eye live together?

Yes. Blind Cave Tetra and Gertrude's Spotted Blue-eye 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 Gertrude's Spotted Blue-eye 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 Gertrude's Spotted Blue-eye together?

Keep the aquarium between 21°C and 25°C. A target of around 23.0°C sits comfortably within both species' preferred ranges.

Are Blind Cave Tetra or Gertrude's Spotted Blue-eye aggressive?

Blind Cave Tetra is generally mild-mannered (4/10) and Gertrude's Spotted Blue-eye is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Blind Cave Tetra and Gertrude's Spotted Blue-eye 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 Gertrude's Spotted Blue-eye's fins?

Blind Cave Tetra is a known fin nipper. If Gertrude's Spotted Blue-eye 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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