Balloon Molly Black (Poecilia sphenops var.)

The Black Balloon Molly is a fully captive-bred aquarium strain of Poecilia sphenops, the Short-finned Molly. The 'balloon' body shape is a result of selective breeding that has produced a characteristic dorsally curved spine and greatly rounded, inflated belly, giving the fish its distinctive silhouette. The jet-black colouration of this variant — a deep, uniform black across the entire body and fins — makes it particularly striking in planted or light-substrate aquariums.

Mollies are livebearers native to Central America and Mexico, inhabiting coastal lowland streams, estuaries, and even brackish and marine environments. They are highly adaptable to a range of water conditions, including freshwater, brackish, and even full marine salinity. In freshwater aquariums, a small amount of aquarium salt (1–2 teaspoons per 10 litres) is beneficial but not mandatory for healthy Mollies.

Like all livebearers, Mollies give birth to fully formed, free-swimming young after a gestation period of approximately 28–35 days. Females can store sperm from a single mating and produce multiple consecutive broods of 20–80 fry. Fry are large enough at birth to accept finely crushed flake or baby brine shrimp immediately.

The balloon body shape, while visually distinctive, represents a compromise in swimming ability — balloon mollies swim with a characteristic wobbling motion and are slower than standard-bodied mollies. They should be housed with similarly slow or docile tank mates to prevent competition at feeding time.

Tank Setup: A 60-litre minimum for a small group. Provide moderate to strong filtration and aeration — mollies are sensitive to poor water quality. Broad-leaved plants (Anubias, Cryptocoryne), floating plants, and open swimming space work well. A lid is recommended as mollies occasionally jump.

Water Parameters: Temperature 24–28°C; pH 7.0–8.5; GH 10–25 °dH; KH 5–15 °dH. Mollies prefer hard, alkaline water. A small amount of aquarium salt (1–2 tsp per 10 L) is beneficial. Avoid very soft acidic water.

Feeding: Omnivore with herbivore tendencies. Feed quality flake food, spirulina-based pellets, algae wafers, blanched vegetables (zucchini, cucumber, spinach), frozen Daphnia, and brine shrimp. Feed two to three times daily.

Tank Mates: Peaceful with most community fish. Suitable with other livebearers (platies, guppies, swordtails), tetras, barbs, corydoras, and small peaceful cichlids. Avoid aggressive fish and fin-nippers.

Behaviour: Generally peaceful and sociable. Males may chase females frequently — maintain a ratio of at least two females per male. Balloon body shape means slower swimming than standard mollies — ensure they can access food.

Health: Mollies are prone to 'Molly disease' (shimmying) — a symptom of poor water quality, cold water, or low salinity. Maintain warm, hard, slightly salty conditions to prevent this. Susceptible to ich when stressed.