Can Molly (Sailfin/Black/Dalmatian) and Turquoise Rainbowfish Live Together?

Reviewed by Guidarium Editorial DeskUpdated April 28, 2026
Possible with Caution

Keeping Molly (Sailfin/Black/Dalmatian) and Turquoise Rainbowfish together is possible but requires caution, though some care is needed. Provide a spacious tank of at least 160 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Molly (Sailfin/Black/Dalmatian)

Poecilia sphenops

Turquoise Rainbowfish

Melanotaenia lacustris

🐠Family Group
Molly (Sailfin/Black/Dalmatian)
Livebearers
Turquoise Rainbowfish
Rainbowfish
Temperament
Molly (Sailfin/Black/Dalmatian)
Mostly Peaceful (3/10)
Turquoise Rainbowfish
Peaceful (2/10)
Temperature
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
24–28°C
Turquoise Rainbowfish
20–25°C
pH Range
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
7.5–8.5
Turquoise Rainbowfish
7–9
Hardness (dGH)
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
12–30
Turquoise Rainbowfish
10–25
Water Type
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
Brackish Tolerant
Turquoise Rainbowfish
Freshwater Only
Flow Preference
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
Moderate
Turquoise Rainbowfish
Moderate
Min Tank Volume
Combined: 160 L
Molly (Sailfin/Black/Dalmatian)
75 L
Turquoise Rainbowfish
160 L
Swimming Level
Shared: 2 zones
Molly (Sailfin/Black/Dalmatian)
TopMiddle
Turquoise Rainbowfish
TopMiddle
🏷️Behavior Tags
Molly (Sailfin/Black/Dalmatian)
Hyperactive / Fast SwimmerFry PredatorAggressive Eater (Starves shy fish)
Turquoise Rainbowfish
Hyperactive / Fast SwimmerJumper (Lid Required)Aggressive Eater (Starves shy fish)
Stocking calculator

Can your tank handle Molly (Sailfin/Black/Dalmatian) and Turquoise Rainbowfish?

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.

Molly (Sailfin/Black/Dalmatian)
Turquoise Rainbowfish
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Behaviour & Temperament

Molly (Sailfin/Black/Dalmatian) is a generally mild-mannered species (3/10), while Turquoise Rainbowfish is peaceful (2/10). This modest difference means Molly (Sailfin/Black/Dalmatian) may occasionally assert dominance over Turquoise Rainbowfish.

Molly (Sailfin/Black/Dalmatian) and Turquoise Rainbowfish both frequent the Top (Surface) and 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: Turquoise Rainbowfish is a known jumper, so a tight-fitting lid is essential.

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

For general hardness, the shared comfort zone is 12–25 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Molly (Sailfin/Black/Dalmatian) and Turquoise Rainbowfish together, plan for an aquarium of at least 160 litres with a minimum length of 120 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, Established Algae (Otocinclus), Plants - lighly covered. 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.

Why This Pairing Needs Extra Planning in Practice

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Molly (Sailfin/Black/Dalmatian) and Turquoise Rainbowfish need extra room, more cover, and closer observation during the first few weeks so small aggression, feeding, or territory issues do not snowball into a long-term problem.

Suitable Tank Sizes

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

Show 5 more tank sizes

Frequently Asked Questions

Can Molly (Sailfin/Black/Dalmatian) and Turquoise Rainbowfish live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 160 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Molly (Sailfin/Black/Dalmatian) and Turquoise Rainbowfish need?

A minimum of 160 litres (tank length at least 120 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 Turquoise Rainbowfish 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 Turquoise Rainbowfish aggressive?

Molly (Sailfin/Black/Dalmatian) is generally mild-mannered (3/10) and Turquoise Rainbowfish is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Molly (Sailfin/Black/Dalmatian) and Turquoise Rainbowfish need?

Both species overlap in the 7.5–8.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Editorial Review

Guidarium Editorial Desk

Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.

Last reviewed
April 28, 2026
Last updated
April 28, 2026
Issues or corrections?
Contact the editorial team

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