Easy

Molly

By The Aquarium Calculators Editorial Team ·

Poecilia sphenops

Complete Molly care guide covering omnivore diet requirements, peaceful temperament, minimum 10 Gallons tank setup, and compatible freshwater tankmates. Difficulty: Easy.

Molly

Quick Answer

Molly (Poecilia sphenops) is a captivating and highly sought-after freshwater species. It requires a minimum 10 Gallons aquarium with a pH of 7.0 - 8.0 and temperature range of 22-26°C. This omnivore occupies the middle zone and makes an excellent addition to community setups.

Intro

Molly (Poecilia sphenops) is a captivating and highly sought-after freshwater species. Known for their peaceful nature and distinct appearance, they occupy the middle levels of the aquarium and bring dynamic energy to any setup.

Setup

Molly requires a stable, well-filtered aquarium of at least 10 gallons. They thrive best with moderate water movement and a reliable heater to maintain temperatures around 22-26°C. Ensure pH levels remain consistent between 7.0 - 8.0 to prevent stress and support long-term health.

Feeding

As a omnivore, the Molly is not a picky eater. They should be fed a high-quality base of flakes, sinking pellets, or wafers. Periodic supplementation with frozen or live foods, such as bloodworms or brine shrimp, will boost their health and colors.

Compatibility

Molly has a peaceful temperament. They are compatible with other fish of similar sizes and temperaments. Avoid placing them with aggressive species or tankmates they are listed as incompatible with, such as: oscar, african cichlid.

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Tank Position
Middle
Water Temp
22-26°C
Adult Size
See profile
Water pH
7.0 - 8.0

Species Characteristics

Adult Size
Lifespan
Growth Rate
moderate
Tank Compatibility
Community compatible
Indoor Aquarium
Yes

Water Parameters

Water Temperature
Humidity
Water pH

Tank Lighting

Tank Lighting
Standard lighting
Light Hours
N/A
Intensity
moderate

Feeding & Diet

Diet Type
Diet: Omnivore
Feeding Schedule
N/A
Live Food Options
N/A

Frequently Asked Questions

How many Mollies should be kept together?
Maintain a group of 4 to 6 individuals in a tank of at least 20 gallons (75 liters) with a footprint of 30x12 inches (75x30 cm). Mollies (Poecilia sphenops) are social livebearers; groups under 4 cause stress and reduced breeding. Maintain a ratio of 2-3 females per male to reduce male harassment. For a male-only display, keep 4-5 males. Provide dense planting (Java moss, Hornwort) and open swimming areas. Tank length must exceed 24 inches (60 cm). They are brackish-tolerant but thrive in freshwater if parameters are stable.
What are the exact water parameters for Mollies?
Target pH 7.0 - 8.0, General Hardness 10 - 20 dGH, Carbonate Hardness 8 - 15 dKH, Total Dissolved Solids 200 - 500 ppm, Electrical Conductivity 400 - 1000 μS/cm, and temperature 72°F - 82°F (22°C - 28°C). They require hard, mineral-rich alkaline water; soft water (dGH <5) causes clamped fins, shimmies, and premature death. Maintain nitrates below 20 ppm with weekly 25% water changes. Add crushed coral or aragonite to increase hardness. Brackish species require specific gravity 1.005-1.010. Avoid low pH below 6.5.
What is the dietary and medication protocol for Mollies?
They are omnivores with a high requirement for plant matter (60% vegetable, 40% protein). Feed spirulina flakes, veggie pellets, blanched zucchini, spinach, and nori sheets daily. Supplement with brine shrimp, bloodworms, and daphnia twice weekly. They graze on algae. Medication alert: Tolerate copper (0.2 mg/L) and formalin. Praziquantel is safe. Salt baths up to 10 ppt treat external parasites (they tolerate higher salinity). Quarantine with methylene blue for 7 days. Susceptible to ich and velvet; treat with malachite green.
How to breed Mollies with step-by-step triggers?
No special triggers needed; they breed prolifically. Maintain temperature at 78°F (25.5°C), pH 7.5, and provide dense java moss for fry. Females give birth to 20-100 live fry every 28-35 days after 4-5 week gestation. Fry are 0.25 inches (6 mm) and accept crushed flakes, baby brine shrimp, and spirulina powder immediately. Remove adults to prevent cannibalism, or provide dense moss. Separate males and females to control population. Add aquarium salt (1-2 ppt) to reduce stress and improve health.