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

Possible with Caution

Keeping Black Ruby Barb and Molly (Sailfin/Black/Dalmatian) together is possible but requires caution, though some care is needed. Provide a spacious tank of at least 80 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Black Ruby Barb

Pethia nigrofasciata

Molly (Sailfin/Black/Dalmatian)

Poecilia sphenops

🐠Family Group
Black Ruby Barb
Cyprinids
Molly (Sailfin/Black/Dalmatian)
Livebearers
Temperament
Black Ruby Barb
Mostly Peaceful (3/10)
Molly (Sailfin/Black/Dalmatian)
Mostly Peaceful (3/10)
Temperature
✓ Compatible
Black Ruby Barb
20–26°C
Molly (Sailfin/Black/Dalmatian)
24–28°C
pH Range
✓ Compatible
Black Ruby Barb
5.5–7.5
Molly (Sailfin/Black/Dalmatian)
7.5–8.5
Hardness (dGH)
✓ Compatible
Black Ruby Barb
2–15
Molly (Sailfin/Black/Dalmatian)
12–30
Water Type
✓ Compatible
Black Ruby Barb
Freshwater Only
Molly (Sailfin/Black/Dalmatian)
Brackish Tolerant
Flow Preference
✓ Compatible
Black Ruby Barb
Moderate
Molly (Sailfin/Black/Dalmatian)
Moderate
Min Tank Volume
Combined: 80 L
Black Ruby Barb
80 L
Molly (Sailfin/Black/Dalmatian)
75 L
Swimming Level
Shared: 1 zone
Black Ruby Barb
MiddleBottom
Molly (Sailfin/Black/Dalmatian)
TopMiddle
🏷️Behavior Tags
Black Ruby Barb
Hyperactive / Fast SwimmerFry PredatorAggressive Eater (Starves shy fish)
Molly (Sailfin/Black/Dalmatian)
Hyperactive / Fast SwimmerFry PredatorAggressive Eater (Starves shy fish)
Stocking calculator

Can your tank handle Black Ruby Barb and Molly (Sailfin/Black/Dalmatian)?

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 Ruby Barb
Molly (Sailfin/Black/Dalmatian)
Test both in my tank

Behaviour & Temperament

Both Black Ruby Barb and Molly (Sailfin/Black/Dalmatian) 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.

Black Ruby Barb and Molly (Sailfin/Black/Dalmatian) 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 26°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 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 12–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Black Ruby Barb and Molly (Sailfin/Black/Dalmatian) together, plan for an aquarium of at least 80 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 — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: Plants - Densely covered, Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Established Algae (Otocinclus). 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.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Black Ruby Barb and Molly (Sailfin/Black/Dalmatian).

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Frequently Asked Questions

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

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 80 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Black Ruby Barb and Molly (Sailfin/Black/Dalmatian) need?

A minimum of 80 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 Ruby Barb and Molly (Sailfin/Black/Dalmatian) together?

Keep the aquarium between 24°C and 26°C. A target of around 25.0°C sits comfortably within both species' preferred ranges.

Are Black Ruby Barb or Molly (Sailfin/Black/Dalmatian) aggressive?

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

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

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


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