Can Molly (Sailfin/Black/Dalmatian) and Rosy Barb Live Together?

🟢Ideal Tank Mates

Yes, Molly (Sailfin/Black/Dalmatian) and Rosy Barb 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

Molly (Sailfin/Black/Dalmatian)

Poecilia sphenops

Rosy Barb

Pethia conchonius

🐠Family Group
Molly (Sailfin/Black/Dalmatian)
Livebearers
Rosy Barb
Cyprinids
Temperament
Molly (Sailfin/Black/Dalmatian)
Mostly Peaceful (3/10)
Rosy Barb
Mostly Peaceful (3/10)
Temperature
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
24–28°C
Rosy Barb
18–25°C
pH Range
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
7.5–8.5
Rosy Barb
6–8
Hardness (dGH)
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
12–30
Rosy Barb
4–15
Water Type
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
Brackish Tolerant
Rosy Barb
Freshwater Only
Flow Preference
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
Moderate
Rosy Barb
Moderate
Min Tank Volume
Combined: 132 L
Molly (Sailfin/Black/Dalmatian)
75 L
Rosy Barb
110 L
Swimming Level
Shared: 1 zone
Molly (Sailfin/Black/Dalmatian)
TopMiddle
Rosy Barb
MiddleBottom
🏷️Behavior Tags
Molly (Sailfin/Black/Dalmatian)
Hyperactive / Fast SwimmerFry PredatorAggressive Eater (Starves shy fish)
Rosy Barb
Hyperactive / Fast SwimmerFin NipperAggressive Eater (Starves shy fish)Plant Destroyer

Behaviour & Temperament

Both Molly (Sailfin/Black/Dalmatian) and Rosy Barb are generally mild-mannered species with an aggression score of 3/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Molly (Sailfin/Black/Dalmatian) and Rosy Barb 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.

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 7.5 and 8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 12–15 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Molly (Sailfin/Black/Dalmatian) and Rosy Barb 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: Plants - Densely covered, Established Algae (Otocinclus). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Rosy Barb is a plant destroyer, which conflicts with Molly (Sailfin/Black/Dalmatian)'s requirement for live plants. Compromise where possible or prioritise the more critical need.

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

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Frequently Asked Questions

Can Molly (Sailfin/Black/Dalmatian) and Rosy Barb live together?

Yes. Molly (Sailfin/Black/Dalmatian) and Rosy Barb are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.

What size tank do Molly (Sailfin/Black/Dalmatian) and Rosy Barb 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 Molly (Sailfin/Black/Dalmatian) and Rosy Barb 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 Molly (Sailfin/Black/Dalmatian) or Rosy Barb aggressive?

Molly (Sailfin/Black/Dalmatian) is generally mild-mannered (3/10) and Rosy Barb is generally mild-mannered (3/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Molly (Sailfin/Black/Dalmatian) and Rosy Barb need?

Both species overlap in the 7.5–8 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Will Rosy Barb nip Molly (Sailfin/Black/Dalmatian)'s fins?

Rosy Barb is a known fin nipper. If Molly (Sailfin/Black/Dalmatian) has long or flowing fins, there is a real risk of fin damage. Keeping Rosy Barb in a larger group can help redirect nipping behaviour toward conspecifics.


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