Can Blind Cave Tetra and Rummy-Nose Tetra Live Together?

🟡Possible with Caution

Keeping Blind Cave Tetra and Rummy-Nose Tetra together is possible but requires caution due to potential behavioral clashes. Provide a spacious tank of at least 132 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Blind Cave Tetra

Astyanax mexicanus

Rummy-Nose Tetra

Hemigrammus rhodostomus

🐟Family Group
Blind Cave Tetra
Characins
Rummy-Nose Tetra
Characins
Temperament
Blind Cave Tetra
Mostly Peaceful (4/10)
Rummy-Nose Tetra
Peaceful (1/10)
Temperature
✓ Compatible
Blind Cave Tetra
20–25°C
Rummy-Nose Tetra
24–28°C
pH Range
✓ Compatible
Blind Cave Tetra
6.5–8
Rummy-Nose Tetra
5.5–7
Hardness (dGH)
✓ Compatible
Blind Cave Tetra
8–20
Rummy-Nose Tetra
1–12
Water Type
✓ Compatible
Blind Cave Tetra
Freshwater Only
Rummy-Nose Tetra
Freshwater Only
Flow Preference
✓ Compatible
Blind Cave Tetra
Moderate
Rummy-Nose Tetra
Moderate
Min Tank Volume
Combined: 132 L
Blind Cave Tetra
110 L
Rummy-Nose Tetra
75 L
Swimming Level
Shared: 2 zones
Blind Cave Tetra
MiddleBottom
Rummy-Nose Tetra
MiddleBottom
🏷️Behavior Tags
Blind Cave Tetra
Hyperactive / Fast SwimmerFin NipperAggressive Eater (Starves shy fish)
Rummy-Nose Tetra
Hyperactive / Fast SwimmerShy / Slow Moving (Easily Stressed)Fry PredatorNano / Bite-sized (Predation Risk)

Behaviour & Temperament

Blind Cave Tetra is a generally mild-mannered species (4/10), while Rummy-Nose Tetra is peaceful (1/10). This modest difference means Blind Cave Tetra may occasionally assert dominance over Rummy-Nose Tetra.

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

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion. Aggressive eaters may outcompete shy fish for food, leading to malnutrition.

To improve the chances of a peaceful coexistence in this community tank: A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat. Keep fin nippers in larger groups to distribute nipping behaviour among conspecifics rather than tank mates.

Water Parameters

The safe temperature window for both species falls between 24°C and 25°C. Aim for the midpoint of this range (around 24.5°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 and 7. 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 Rummy-Nose 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.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: Smooth Gravel (Sensitive Barbels), Plants - Densely covered, Plants - lighly covered, 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.

Diet & Feeding

Feeding time deserves special attention with this pairing. Blind Cave Tetra is an aggressive eater that may prevent Rummy-Nose Tetra from getting enough food.

Because Blind Cave Tetra is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Rummy-Nose Tetra receives an adequate share.

Frequently Asked Questions

Can Blind Cave Tetra and Rummy-Nose Tetra live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 132 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Blind Cave Tetra and Rummy-Nose 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 Rummy-Nose Tetra together?

Keep the aquarium between 24°C and 25°C. A target of around 24.5°C sits comfortably within both species' preferred ranges.

Are Blind Cave Tetra or Rummy-Nose Tetra aggressive?

Blind Cave Tetra is generally mild-mannered (4/10) and Rummy-Nose Tetra is peaceful (1/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Blind Cave Tetra and Rummy-Nose Tetra need?

Both species overlap in the 6.5–7 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Will Blind Cave Tetra nip Rummy-Nose Tetra's fins?

Blind Cave Tetra is a known fin nipper. If Rummy-Nose 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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