Black Molly

Poecilia sphenops

Photo of aquarium fish Black Molly
Natural range
  • Mexico area
  • Central America area
  • Colombia area
  • Venezuela area
LivebearersConservation status: Least concern LC

Family:Poeciliidae

Other scientific names: Gambusia modesta, Gambusia plumbea, Lembesseia parvianalis, Mollienesia altissima, Mollienesia macrura, Mollienesia pallida

The Black Molly, often simply called Black Molly, is apparently a selective color variation of the well-known Sailfin Molly (Poecilia sphenops). At the same time, some authoritative breeders prefer the version that it originated from the Liberty Molly (Poecilia latipinna). There is no precise and undeniable information about the true lineage of this form, but for most aquarists, this is not of fundamental importance, as it does not affect the requirements for its keeping.

Required aquarium volume
100 L
Size in aquarium
8 – 10 cm
Temperature
24 – 27 °C
Temperament
Peaceful (regular)
Parameters
Temperature24 – 27 °C
Water pHNeutral (7) – Slightly alkaline (8.5)
Water dHMedium hardness (11) – Very hard (30)
Water salinitymoderate (5–10 g/L)
Size in aquarium8 – 10 cm
Lifespan5 years
TemperamentPeaceful (regular)
Toward small fishnot a predator
Required aquarium volume100 L
Lightingany
Substrateany (no restrictions)
Water flowweak
FeedingMixed diet (meat + plant-based)
CareMixed (solitary / pair / group)

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Black Molly get?

An adult reaches 8–10 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Black Molly need?

The minimum recommended volume is 100 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Black Molly need?

Temperature 24–27 °C, pH 7–8.5, hardness 11–30 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Black Molly live?

Around 5 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Black Molly aggressive?

Temperament: peaceful (regular). Keep this in mind when choosing tank mates.

How many Black Molly should be kept together?

Recommended setup: mixed (solitary / pair / group). Ignoring this is a common cause of stress and disease.

What does Black Molly eat?

Diet type: mixed diet (meat + plant-based). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Black Molly?

The scientific name of the species is Poecilia sphenops, family Poeciliidae. It also appears in the literature as: Gambusia modesta, Gambusia plumbea, Lembesseia parvianalis.

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