Black Molly
Poecilia sphenops
The Black Molly is the embodiment of perfect melanism in aquariums. However, the myth of its hardiness is false. These fish evolved in estuaries, where the sea meets rivers. They demand extremely hard, alkaline, and very warm water (26°C), often with added marine salt (brackish). Putting them in a normal soft-water aquarium equals dissolving their immune system. They will start to rock in place ("Shimmying"), and then cover themselves in lethal white spots (Ich) within hours due to osmosis destroying their protective mucus.
Température de l’eau
22 - 28 °C
Valeur du pH
7.5 - 8.5
Type d'eau
Eau douce / Eau saumâtre
Niveau dans le bac
Surface et milieu
Taille adulte
7 cm
Volume minimal du bac
>= 80 L
Groupe minimal
>= 4
GH
15 - 30 dGH
KH
7 - 15 dKH
TDS
295 - 600 ppm
Conductivité
461 - 938 uS/cm
Description de l'espèce
Geographical Origin and Habitat: Commercial hybrid. The wild form (P. sphenops) comes from canals, coastal rivers and brackish water swamps of Central-South America (Mexico, Colombia). The Black Molly is the result of crossbreeding to fix melanism.
Taxonomy and Morphology: Black Molly (Poecilia sphenops). Lively poeciliid. Fusiform and hydrodynamic body, mouth adapted to scrape algae from surfaces. A very rustic strain (short-fin) compared to the sailfins.
Social Behavior: Incessant explorer and grazer. Wanders around the tank continuously "pecking" woods, glass and leaves. Males engage in relentless chases to mate, becoming bothersome if there are too few females.
Coloration and Sexual Dimorphism: Total Darkness. The color is an intense anthracite black over the entire body, fins included, almost velvety. If there are gold reflections, it is not a pure strain. Males (5 cm / 2 inches) with pointed gonopodium, females rounder and larger (7 cm / 2.7 inches).
Soins, reproduction et cohabitation
Aquarium Setup: Spacious community tank (minimum 80 cm / 32 inches). Many robust plants (Vallisneria, Microsorum) and woods. They need free swimming. They appreciate a gentle water flow for oxygenation.
Diet and Feeding: Algae-grazing machine. Many buy them to eliminate filamentous or brush algae (BBA). In the tank they must follow a 70% vegetable diet (spirulina flakes, boiled zucchini, peeled peas) to avoid occlusions.
Water Quality: Lifesaving Salt. Mollies are not pure freshwater fish. They demand VERY HARD (GH 15-30) and alkaline (pH 8) water. Adding 1-2 teaspoons of marine salt per 10 liters (2.5 Gallons) will make them immortal; in soft freshwater, they will get "Shimmy" disease in a few days.
Compatibility and Cohabitation: Excellent community dweller, provided everyone loves hard water. Perfect with Guppies, Platies, Swordtails. Not recommended pairing with Amazonian Characins (Neons) which need soft and acidic waters.
Aquarium Breeding: Ovoviviparous. No nests or eggs. The female expels 20-60 large and black fry once a month, perfectly autonomous. Without hiding places, adults and tankmates will feast on them.
Risks and Diseases: The Shimmy Disease. Symptom of osmotic stress from water that is too soft (little calcium and salts). The Molly seems to swim in place rocking its head (like a snake), clamps its fins and eventually dies. It is cured instantly by adding mineral or marine salt.
Origine et répartition géographiques
Commercial hybrid. The wild form (P. sphenops) comes from canals, coastal rivers and brackish water swamps of Central-South America (Mexico, Colombia). The Black Molly is the result of crossbreeding to fix melanism.
Origine
Sélection et cultivarsAmérique du Sud hors AmazonieAmérique centrale et Caraïbes
Profil de poisson
- Tempérament
- Active
- These fish have an active, outgoing, and generally peaceful temperament. They are robust and bold, often the first to greet their keeper during feeding times. While males can display some boisterous behavior towards one another, severe aggression is highly uncommon. Their energetic and inquisitive nature brings a lot of liveliness to any community aquarium. Given enough space, they interact very well with their environment and tank mates.
- Régime alimentaire
- Omnivore
- As omnivores with an inclination towards herbivory, a large portion of their diet should consist of vegetable matter. High-quality spirulina flakes or algae wafers are excellent staple choices. They will also eagerly consume live or frozen foods like brine shrimp, bloodworms, and daphnia. Offering blanched vegetables like zucchini or spinach provides valuable roughage. A diet rich in plant matter prevents digestive blockages and promotes vibrant health.
- Espérance de vie
- 3-5 years
- Taille adulte
- 7 cm
- Ratio des sexes
- Specific M:F ratio
- It is crucial to maintain a ratio of at least two to three females per male. Male mollies are persistent in their mating behaviors and can relentlessly chase females. A proper ratio diffuses this attention, significantly reducing the stress placed on any single female. Persistent stress from excessive males can lead to illness or even death for the females. Observing this ratio ensures a more peaceful dynamic within the aquarium.
- Fréquence d'alimentation
- Twice daily
- Feeding them two to three times a day in small portions is the ideal approach. This frequent feeding schedule caters to their highly active metabolism and continuous foraging nature. Ensure each meal is small enough to be entirely consumed within a few minutes. Overfeeding can lead to rapid water degradation given their higher bioload. Offering a variety of foods across these feedings ensures comprehensive nutrition.
- Charge biologique
- Low to Medium
- They produce a moderate to high bioload, especially when compared to smaller livebearers. This is due to their relatively robust size and hearty appetite. Efficient filtration and regular water changes are crucial to process their waste effectively. Inadequate tank maintenance can lead to a quick buildup of harmful nitrates. Monitoring their population size is also important, as their breeding can compound the bioload significantly.
- Courant
- Stagnant
- They are adaptable but generally prefer a moderate water flow in the aquarium. A flow that provides good water circulation without pushing them around is perfect. Adequate water movement also helps in maintaining high oxygenation levels, which they appreciate. Powerheads can be used, but areas of calmer water should be available for resting. In larger tanks, a robust filtration system naturally creates an ideal flow dynamic.
- Risque de saut
- Yes
- They have a notable propensity for jumping, especially when newly introduced to a tank or during active breeding pursuits. A sudden change in lighting or water parameters can also startle them into jumping. It is highly advised to use a tight-fitting aquarium lid or hood at all times. Leaving even small gaps near filters or heaters can lead to an unfortunate escape. Floating plants can mitigate this risk by creating a natural barrier at the surface.
- Reproduction
- Oviparous
- They are prolific livebearers, meaning the females give birth to fully formed, free-swimming fry. Breeding requires virtually no effort if both sexes are present in appropriate water conditions. A single mating can result in several consecutive broods, as females can store sperm. The fry are relatively large compared to other livebearers and can eat crushed flakes immediately. Heavy planting is recommended to provide the fry with shelter from predatory adults.
- Compatibilité et compagnons
- Harem only
- They are generally peaceful community fish, suitable for keeping with a wide variety of similarly sized, non-aggressive species. However, they can occasionally be nippy or boisterous, so very shy or delicate fish might not be the best companions. They do well with robust tetras, corydoras, and other livebearers. In brackish setups, their potential tank mates change significantly. Providing enough space reduces any potential territorial squabbles among themselves and others.
- Niveau dans le bac
- Top/Middle
- They are highly active and will readily explore every level of the aquarium. However, they spend a considerable amount of time in the middle and upper levels of the water column. They are particularly active near the surface during feeding time, eagerly anticipating food. Providing open swimming areas in the middle layers is beneficial for their energetic nature. Their constant movement throughout the tank makes them an excellent display fish.
Modèles et paramètres scientifiques
FishBase
Fenêtre sur les données scientifiques officielles de l’espèce
FishBase v25.04Données synchronisées le : 15/06/2026
- Niveau trophique
- 3 ± 0,34 se
- Résilience
- Élevée (moins de 15 mois)
- Singularité phylogénétique (PD50)
- 0.5
- Relation bayésienne longueur-poids
- a = 0.01514, b = 3.12
- VulnérabilitéVulnérabilité faible (10 / 100)
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