Can Black Acara and Blind Cave Tetra Live Together?

Possible with Caution

Keeping Black Acara and Blind Cave Tetra together is possible but requires caution, though some care is needed. Provide a spacious tank of at least 115 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Black Acara

Cichlasoma bimaculatum

Blind Cave Tetra

Astyanax mexicanus

🐠Family Group
Black Acara
Cichlids - South American
Blind Cave Tetra
Characins
Temperament
Black Acara
Semi-Aggressive (6/10)
Blind Cave Tetra
Mostly Peaceful (4/10)
Temperature
βœ“ Compatible
Black Acara
22–28Β°C
Blind Cave Tetra
20–25Β°C
pH Range
βœ“ Compatible
Black Acara
6–7.5
Blind Cave Tetra
6.5–8
Hardness (dGH)
βœ“ Compatible
Black Acara
4–15
Blind Cave Tetra
8–20
Water Type
βœ“ Compatible
Black Acara
Freshwater Only
Blind Cave Tetra
Freshwater Only
Flow Preference
βœ“ Compatible
Black Acara
Low
Blind Cave Tetra
Moderate
Min Tank Volume
Combined: 115 L
Black Acara
115 L
Blind Cave Tetra
110 L
Swimming Level
Shared: 2 zones
Black Acara
MiddleBottom
Blind Cave Tetra
MiddleBottom
🏷️Behavior Tags
Black Acara
Territorial (Defends specific area)Digger (Disturbs Substrate)Fry Predator
Blind Cave Tetra
Hyperactive / Fast SwimmerFin NipperAggressive Eater (Starves shy fish)
Stocking calculator

Can your tank handle Black Acara and Blind Cave Tetra?

Compatibility is only part of the answer. Test both fish with your real tank size, current stock, and maintenance needs to see if you have enough space and a safe stocking level before you add them.

Black Acara
Blind Cave Tetra
Test both in my tank

Behaviour & Temperament

Black Acara is a moderately assertive species (6/10), while Blind Cave Tetra is generally mild-mannered (4/10). This modest difference means Black Acara may occasionally assert dominance over Blind Cave Tetra.

Black Acara and Blind Cave 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.

To improve the chances of a peaceful coexistence in this community tank: Provide a significantly larger tank (at least 50% more volume than the minimum) to allow both Black Acara and Blind Cave Tetra to establish separate territories. Add plenty of line-of-sight breaks using driftwood, rocks, and dense planting to reduce territorial confrontations. 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 22Β°C and 25Β°C. Aim for the midpoint of this range (around 23.5Β°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.

Tank Setup

To house Black Acara and Blind Cave Tetra together, plan for an aquarium of at least 115 litres with a minimum length of 80 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

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

Specific environmental needs for this combination include: Sand (Sifters), Driftwood (Digestion/Hiding), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

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

Suitable Tank Sizes

Standard aquarium sizes large enough for both Black Acara and Blind Cave Tetra.

Show 10 more tank sizes

Frequently Asked Questions

Can Black Acara and Blind Cave Tetra live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 115 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Black Acara and Blind Cave Tetra need?

A minimum of 115 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 Black Acara and Blind Cave Tetra together?

Keep the aquarium between 22Β°C and 25Β°C. A target of around 23.5Β°C sits comfortably within both species' preferred ranges.

Are Black Acara or Blind Cave Tetra aggressive?

Black Acara is moderately assertive (6/10) and Blind Cave Tetra is generally mild-mannered (4/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Black Acara and Blind Cave Tetra need?

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

Will Blind Cave Tetra nip Black Acara's fins?

Blind Cave Tetra is a known fin nipper. If Black Acara 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.

How do I manage Black Acara's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Black Acara space to claim a territory without encroaching on the other fish's area. Adding dΓ©cor that divides the tank into distinct zones works especially well.


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