Molly

Larger livebearers that appreciate hard, slightly alkaline water and some vegetable matter in their diet. Regular births mean a busy, ever-changing tank.

• Minimum footprint: 20 gallons; a 25+ gallon tank gives real swimming room.
• Preferred swimming zone: middle of the water column.
• Social — keep a group of at least 3.
• Care level: easy.

• Temperature: 72–82°F
• pH: 7.5–8.5
• Hardness: 12–30 dGH (Hard)

Stable parameters matter more than perfect ones — aim for consistency before chasing an exact number.

peaceful

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An omnivore — offer a staple flake or pellet plus regular frozen or live foods (daphnia, bloodworm, brine shrimp) and some vegetable matter for balance.

• Guppy
• Bronze Corydoras
• Harlequin Rasbora
• Zebra Danio
• Platy
• Cherry Barb

A further 1 species pair with Molly as conditional — workable with the right tank and precautions.

• Neon Tetra — pH requirements do not intersect — one species will be stressed.
• Kuhli Loach — pH requirements do not intersect — one species will be stressed.
• Cardinal Tetra — pH requirements do not intersect — one species will be stressed.
• Rummy-Nose Tetra — pH requirements do not intersect — one species will be stressed.
• Ember Tetra — pH requirements do not intersect — one species will be stressed.
• German Blue Ram — pH requirements do not intersect — one species will be stressed.

Standard tanks at or above the recommended 25 gallons:

• 29 gallon 30 × 12 × 18″
• 30 gallon 36 × 12 × 16″
• 40 gallon Breeder 36 × 18 × 16″
• All tank sizes

• Start from a 20 gallon minimum and plan the full group size (3+) before you buy.
• Activity level is moderate, which affects how much of the tank it uses and how much it adds to the bioload.
• Zoning matters: this species lives mostly in the middle zone, so choose tank mates that occupy other levels.

Compatibility depends on tank size, water chemistry, temperament, and adult size. Run a full check against any species in our database.

In-depth guides for Molly:

• Molly and GuppyGood Match
• Molly and PlatyGood Match

• FishBase(Scientific Database, accessed 2026-09-20)
• SeriouslyFish(Specialist Publication, accessed 2026-09-20)
• Aquarium Forge editorial guidelines(Editorial Interpretation, accessed 2026-09-22)

Data reviewed: September 2026 · Data version: 2026.11
Editorial note: Minimum tank recommendations may vary by source and husbandry approach. Our figures synthesise the sources above for planning purposes.