Complete Molly Fish Care Guide

Mollies come in numerous varieties created through selective breeding.

Common Types - Black Molly: Solid black, classic variety - Dalmatian Molly: White with black spots - Gold/Orange Molly: Bright golden color - Silver Molly: Metallic silver sheen - Balloon Molly: Round body shape (controversial)

Fin Types - Common/Short-fin: Standard finnage - Sailfin Molly: Large, impressive dorsal fin - Lyretail: Extended tail fin rays

Sailfin Mollies - Larger than common mollies (up to 5-6 inches) - Need bigger tanks (30+ gallons) - Impressive dorsal fin display - Males larger than females

Note on Balloon Mollies Balloon mollies have compressed spines causing their round shape. Some consider this unethical breeding. They may have shorter lifespans and health issues.

Mollies have specific water preferences that differ from many community fish.

Water Parameters - Temperature: 72-82°F - pH: 7.5-8.5 (prefer alkaline) - Hardness: 15-30 dGH (prefer hard water) - Ammonia/Nitrite: 0 ppm

Why Hard, Alkaline Water? - Mollies evolved in hard water environments - They struggle in soft, acidic water - Can even tolerate brackish conditions - This sets them apart from many tropicals

Brackish Tolerance - Mollies can thrive in brackish water - 1-2 tablespoons salt per gallon - Not required but beneficial for some - Research before mixing with other species

Freshwater is Fine Despite brackish tolerance, mollies do well in fresh hard water. Don't add salt to community tanks without research.

Setting up a proper molly tank ensures healthy, active fish.

Tank Size - 20 gallons minimum - 30+ gallons for sailfin varieties - More space = healthier fish

Filtration - Moderate to strong filtration - Mollies appreciate clean water - Some water movement is good

Plants - Live plants recommended - Java fern, hornwort, Vallisneria - Provide hiding spots for fry - Mollies may nibble on soft plants

Substrate - Sand or gravel both work - Light colors show off dark mollies - Easy to clean is important

Decorations - Provide hiding spots - Open swimming areas - Avoid sharp objects

Mollies are livebearers that breed readily in home aquariums.

Sexing Mollies - Males: Smaller, pointed anal fin (gonopodium) - Females: Larger, fan-shaped anal fin, gravid spot - Males often more colorful - Sailfin males have larger dorsal fins

Breeding - Mollies breed readily without intervention - Keep ratio of 2-3 females per male - Males can harass females constantly - Gestation: 4-6 weeks

Giving Birth - Females give birth to 20-100 live fry - May eat their own fry - Provide dense plants or breeding box - Remove pregnant female before birth

Raising Fry - Feed crushed flakes or baby brine shrimp - Separate from adults if possible - Fast-growing with good food - Sex becomes apparent at 2-3 months

Controlling Population - Mollies breed prolifically - Keep only one sex to prevent breeding - Local fish stores may take juveniles - Some fry will be eaten naturally

Mollies are generally hardy but prone to certain conditions.

Molly Disease (Shimmies) - Symptoms: Rocking motion, unable to swim properly - Cause: Poor water quality, wrong parameters - Treatment: Improve water conditions, add salt - Often indicates water is too soft/acidic

Ich - Common in new or stressed fish - White spots on body - Raise temperature, add salt, medicate

Fin Rot - Ragged, deteriorating fins - Caused by poor water quality - Clean water and medication

Columnaris - White patches, rapid decline - Bacterial infection - Requires antibiotic treatment

Prevention - Maintain proper water parameters - Hard, alkaline water is key - Regular water changes - Quarantine new fish - Avoid sudden parameter changes