Molly
Also known as: Poecilia sphenops
Mollies (Poecilia sphenops) are hardy, adaptable livebearers known for their varied coloration and ability to tolerate a wide range of water conditions, including brackish environments. The Molly originates from Native to freshwater and brackish waters of Mexico, Central America, and northern South America, including rivers, streams, and coastal lagoons from Veracruz, Mexico to Colombia and Venezuela., reaches 10 cm in captivity, typically lives 3, and is kept at 24C (75F). Individual fish vary, so treat this as a general guide rather than a guarantee.
Key facts
- Lifespan: 3.
- Adult size: 10 cm (4 in).
- Temperament: Peaceful and social; active swimmers that thrive in groups and are generally non-aggressive toward tankmates.
- Minimum tank: 75 L (20 gal).
- Water temperature: 24C (75F).
- pH range: pH 7.5-8.5.
Species at a glance
- Origin
- Native to freshwater and brackish waters of Mexico, Central America, and northern South America, including rivers, streams, and coastal lagoons from Veracruz, Mexico to Colombia and Venezuela.
- Adult size
- 10 cm (4 in)
- Life span
- 3
- Temperament
- Peaceful and social; active swimmers that thrive in groups and are generally non-aggressive toward tankmates.
- Tank size
- 75 L (20 gal)
- Water temp
- 24C (75F)
- pH range
- pH 7.5-8.5
- Diet
- Omnivorous; accepts high-quality flake food, micro pellets, blanched vegetables (zucchini, spinach), and occasional live or frozen foods like brine shrimp and daphnia.
- Other names
- Poecilia sphenops
About the Molly
Mollies (Poecilia sphenops) are hardy, adaptable livebearers known for their varied coloration and ability to tolerate a wide range of water conditions, including brackish environments. They are prolific breeders, giving birth to live young after internal fertilization. Males are typically smaller and more colorful than females, often displaying elongated dorsal and anal fins. Mollies are active algae grazers and contribute to tank cleanliness while adding vibrant movement to community aquariums.
Lifespan and health
With proper care, mollies typically live 2–5 years in captivity, though 3 years is the average lifespan reported in home aquariums. Females may have slightly shorter lifespans due to the energetic costs of frequent breeding, especially if not given breaks between broods. Genetics, water quality, and diet play significant roles in longevity; fish kept in stable, well-maintained environments with optimal nutrition often reach the upper end of their lifespan range. Common health issues include fin rot (often from poor water quality or aggression), ich (white spot disease) during temperature fluctuations, and fungal infections following injury. Mollies are also prone to swim bladder disorders if overfed or fed low-quality food. Preventive measures include maintaining stable parameters, quarantining new fish, and providing a varied diet. Prompt treatment with appropriate medications and improved husbandry usually resolves most ailments.
Overview
Mollies (Poecilia sphenops) are hardy, adaptable livebearers known for their varied coloration and ability to tolerate a wide range of water conditions, including brackish environments. They are prolific breeders, giving birth to live young after internal fertilization. Males are typically smaller and more colorful than females, often displaying elongated dorsal and anal fins. Mollies are active algae grazers and contribute to tank cleanliness while adding vibrant movement to community aquariums.
Care and tank setup
Mollies require a minimum tank size of 75 liters (20 gallons) for a small group, with larger tanks recommended for breeding or mixed communities. Provide plenty of swimming space along with live or artificial plants (such as Java fern or Anubias) and hiding spots using driftwood or rocks to reduce stress. A sandy or fine gravel substrate is ideal, and moderate water flow mimics their natural habitat. Maintain water temperature between 24–28°C (75–82°F) and pH between 7.5–8.5; they tolerate slightly brackish water (up to 1.005 specific gravity) but do not require it. Perform weekly 25% water changes to keep nitrate levels below 20 ppm. Use a reliable filter rated for at least twice the tank volume, and ensure good oxygenation, especially in warmer water. Feed mollies 2–3 times daily with small portions they can consume within 2–3 minutes. Their diet should be primarily plant-based, supplemented with protein-rich foods 2–3 times per week. Overfeeding leads to poor water quality and health issues, so monitor feeding amounts carefully. Remove uneaten food after 5 minutes to prevent decomposition.
Sources
Related breeds
Breed information on this page is based on the Wikipedia article on the Molly, supplemented with additional research. Reviewed for accuracy.