🐠Molly: gear and buying guides

The molly is an active, sociable livebearer that reaches 6 to 10 cm and needs more room than a guppy: 100 L minimum. It requires warm water at 24 to 28 °C, hard and alkaline, with some strains even tolerating slight salinity. A keen algae grazer, it enlivens the surface and decor all day long.

Profile : 6 to 10 cm as an adult, 100 L minimum for a group, hard water between 24 and 28 °C.

Species profile

Lifespan

3 to 5 years

Adult size

10 cm

Minimum tank

100 L

Water temperature

24 to 28 °C

pH

7.5 to 8.5

Temperament

Active, sociable and a keen grazer, it enlivens the surface and decor all day in a female-dominant group.

Health watch

shimmying disease in unsuitable water · white spot disease in weakened fish

🩺 This health information is general in nature and does not replace a consultation: at the slightest doubt about your animal’s condition, talk to your vet.

Molly gear, family by family

• 🍖 Food

  Strongly vegetarian: spirulina and blanched vegetables should dominate, supplemented with flakes and occasional frozen foods. A lack of plant matter weakens its digestive system.

• 🧴 Care & grooming

  Delicate in soft acidic water, where it readily develops the shimmying disease. Keep the water hard, alkaline and warm, with a 25 percent weekly water change.

• 🎾 Toys & enrichment

  Sturdy plants that tolerate hard water, calcareous rocks and algae-covered grazing surfaces. It enjoys gentle surface agitation and areas with some current.

• 🏠 Bedding & habitat

  A tank of at least 100 L, fairly tall and long, for a group with a majority of females. A prolific species: plan ahead for the many fry.

• 🧳 Travel & safety

  Warm bag transport is essential, as it copes poorly with temperature drops. Gradual acclimation of 30 to 45 minutes, especially if water hardness differs.

• 🧰 Accessories

  A 100 to 150 W heater, generous filtration, GH/KH tests and possibly mineral salts to reharden the water. Budget around 120 to 200 euros for a 100 to 150 L tank.

Guides to read

• Community aquarium or species-only tank: which is right for a first setup?Bedding & habitat

  Community aquarium or species-only tank: pros, cohabitation risks and advice for choosing how to set up your first aquarium.

• Best easy aquarium plants without CO2 for beginnersToys & enrichment

  Which aquarium plants can you choose without CO2 injection? A selection of hardy, easy plants for a beginner's planted tank.

• Budget for a first brackish water aquarium: the real cost to get startedBedding & habitat

  How much does a first brackish water aquarium cost? Tank, filtration, salt and salinity monitoring, budgeted item by item.

• Changing filter media too often: the mistake that wrecks your aquarium's cycleCare & grooming

  Why you should never replace all your filter media at once: nitrifying bacteria, replacement frequency and the right habits.

• Restarting a neglected aquarium: a step-by-step guideCare & grooming

  How do you restart an aquarium that's been left neglected without endangering the fish? Steps, water changes and mistakes to avoid.

• GH, KH and pH: understanding and adjusting aquarium water hardnessCare & grooming

  GH, KH, pH: what do these three readings actually measure, and how do you adjust aquarium water hardness without stressing the fish?

• Upgrading to a bigger aquarium: moving your fish without the stressBedding & habitat

  How do you upgrade to a bigger aquarium without breaking the biological cycle or stressing your fish? Steps and mistakes to avoid.

• Aquarium electrical safety: GFCI protection and good habitsTravel & safety

  Heater, filter, lighting near the water: what electrical precautions keep an aquarium safe for fish and people?