Can Molly (Sailfin/Black/Dalmatian) and Neon Tetra Live Together?

🔴Not Recommended

Molly (Sailfin/Black/Dalmatian) and Neon Tetra are not recommended as tank mates due to incompatible hardness ranges. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Molly (Sailfin/Black/Dalmatian)

Poecilia sphenops

Neon Tetra

Paracheirodon innesi

🐠Family Group
Molly (Sailfin/Black/Dalmatian)
Livebearers
Neon Tetra
Characins
Temperament
Molly (Sailfin/Black/Dalmatian)
Mostly Peaceful (3/10)
Neon Tetra
Peaceful (1/10)
Temperature
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
24–28°C
Neon Tetra
20–26°C
pH Range
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
7.5–8.5
Neon Tetra
5–7.5
Hardness (dGH)
✗ No overlap
Molly (Sailfin/Black/Dalmatian)
12–30
Neon Tetra
1–10
Water Type
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
Brackish Tolerant
Neon Tetra
Freshwater Only
Flow Preference
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
Moderate
Neon Tetra
Moderate
Min Tank Volume
Combined: 90 L
Molly (Sailfin/Black/Dalmatian)
75 L
Neon Tetra
38 L
Swimming Level
Shared: 1 zone
Molly (Sailfin/Black/Dalmatian)
TopMiddle
Neon Tetra
Middle
🏷️Behavior Tags
Molly (Sailfin/Black/Dalmatian)
Hyperactive / Fast SwimmerFry PredatorAggressive Eater (Starves shy fish)
Neon Tetra
Nano / Bite-sized (Predation Risk)Hyperactive / Fast Swimmer

Behaviour & Temperament

Molly (Sailfin/Black/Dalmatian) is a generally mild-mannered species (3/10), while Neon Tetra is peaceful (1/10). This modest difference means Molly (Sailfin/Black/Dalmatian) may occasionally assert dominance over Neon Tetra.

Molly (Sailfin/Black/Dalmatian) and Neon Tetra 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.

Hardness requirements are incompatible: Molly (Sailfin/Black/Dalmatian) needs 12–30 dGH while Neon Tetra requires 1–10 dGH. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Molly (Sailfin/Black/Dalmatian) and Neon Tetra together, plan for an aquarium of at least 90 litres with a minimum length of 60 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), Leaf Litter/Blackwater, Plants - Floating. 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

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Frequently Asked Questions

Can Molly (Sailfin/Black/Dalmatian) and Neon Tetra live together?

No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.

What size tank do Molly (Sailfin/Black/Dalmatian) and Neon Tetra need?

A minimum of 90 litres (tank length at least 60 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 Neon Tetra 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 Molly (Sailfin/Black/Dalmatian) or Neon Tetra aggressive?

Molly (Sailfin/Black/Dalmatian) is generally mild-mannered (3/10) and Neon Tetra is peaceful (1/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Molly (Sailfin/Black/Dalmatian) and Neon Tetra 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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