Sailfin Molly

Sailfin mollies are fascinating brackish and freshwater fish closely related to Guppies. With their remarkable dorsal fins and diverse colors, they have earned a special place in the hearts of aquarium hobbyists. These sociable fish require straightforward care, making them an outstanding selection for community tanks.

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Care DIfficulty


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Southern United States, Mexico, and Central America

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4 inches (10 cm)

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5 years

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Table of contents

Origin, Appearance, Size, and Lifespan

The Sailfin Molly, or Poecilia latipinna, often referred to as the Sailfin, is a beloved brackish and freshwater fish originating from the coastal waters and rivers of the Southeastern United States. They are commonly found in the coastal waters of North Carolina down to Texas and the Yucatan Peninsula of Mexico.

In their natural habitat, Sailfin Mollies are usually seen in calm, shallow waters abundant in vegetation. These plants serve dual purposes - providing cover and contributing to their diet, while the dark river bottoms highlight their diverse coloration. These social fish prosper in groups, often seen in large schools.

Their natural environment consists of warm, slightly alkaline to brackish water. The temperature generally ranges from 72 to 82 degrees Fahrenheit (22 to 28 degrees Celsius), with a pH level of 7.5 to 8.5, and water hardness between 20 to 30 dGH. To recreate a similar environment in your aquarium, ensure a stable water temperature, employ a high-grade filtration system, and incorporate live plants and rocks.

By carefully emulating the Sailfin Molly's natural setting and maintaining the appropriate water conditions, you can ensure your fish lead a content and healthy life in your aquarium.

Sailfin Mollies are admired for their impressive sail-like dorsal fins, which can be raised or lowered depending on their mood. Their bodies display a wide range of colors, from silver and gold to black, and sometimes even a mix, making them a visually enticing addition to aquariums. Despite their small size, typically growing up to 4 inches (10 cm) in length, their unique fins and lively behavior make them an optimal choice for those desiring an energetic, colorful aquatic display. These delightful fish captivate onlookers as they gracefully navigate through the tank, earning them a beloved spot among enthusiasts of all skill levels.

With appropriate care, Sailfin Mollies can live up to five years. Being social creatures, they thrive in groups and are ideally kept in schools of a minimum of five members. To foster their health and ensure longevity in captivity, it's crucial to provide an aquarium teeming with plants and hiding spots, along with a varied diet of high-quality flakes, pellets, and live foods.

Fun Facts

Having explored the appearance and lifespan of Sailfin Mollies, let's delve into this section that sheds light on some intriguing facts about these charming fish. From their distinctive fins to their social behavior, Sailfin Mollies are packed with captivating attributes that are sure to enchant any aquarist.

  • Adaptability: Sailfin Mollies are noteworthy for their ability to adapt to a variety of water conditions. They can live in fresh, brackish, or even saltwater environments, exhibiting an impressive level of adaptability not seen in many other aquarium fish.
  • Unique Fin Display: The Sailfin Molly is named after its most striking feature: the large, sail-like dorsal fin. Males use these fins to impress females during mating rituals, making them one of the few fish species where males are more colorful and attractive than females.
  • Livebearers: Sailfin Mollies are livebearers, meaning they give birth to live young instead of laying eggs. This unique reproductive method allows them to rapidly populate a tank under the right conditions.
  • Color Variation: Sailfin Mollies come in a wide range of colors, from silver and black to gold and dalmatian. This color diversity makes them a visually appealing addition to any aquarium.
  • Social Nature: Sailfin Mollies are social fish that prefer to live in groups. This behavior not only helps them feel secure but also creates an attractive visual spectacle in the aquarium. Their social interactions and vibrant colors can turn a home aquarium into a captivating underwater display.

After uncovering these fascinating facts about Sailfin Mollies, you're now better prepared to appreciate their allure and complexities in your own aquarium. In the subsequent section, we will provide advice on tank setups, ensuring your Sailfin Mollies have the perfect environment to flourish and exhibit their alluring features.

Recommended Tank Setups

Each setup includes the key components—tank, filter, heater, lighting, substrate, and more—to provide a fitting environment for Sailfin Mollies and other compatible freshwater and brackish water species in your aquarium. As you progress from cost-effective to premium setups, you'll discover more choices for personalization, aesthetics, and advanced capabilities. Sailfin Mollies are social fish that should be kept in groups of at least five to alleviate stress and promote their welfare. Generally, Sailfin Mollies cost between $3 and $6 per fish, although prices can fluctuate based on factors such as size, quality, and availability.

Budget-friendly setup (around $200):

  • Tank: 20-gallon aquarium with a lid or glass canopy ($40 - $70)
  • Filter: Hang-on-back (HOB) or sponge filter rated for 20 gallons ($20 - $40)
  • Heater: 50-100 watt adjustable aquarium heater ($15 - $30)
  • Lighting: Basic LED aquarium light ($20 - $50)
  • Substrate: Budget-friendly aquarium sand or small gravel ($10 - $20)
  • Decor: A few pieces of driftwood and rocks, along with economical live plants like Java Fern and Anubias ($20 - $40)
  • Fish: Minimum 5, maximum 10 Sailfin Mollies ($15 - $30)
  • Thermometer: $3 - $10
  • Substrate Vacuum: $10 - $25
  • Fish Net: $2 - $10
  • Algae Scraper or Magnetic Cleaner: $5 - $20
  • Siphon and Bucket: $15 - $30
  • Test Kit: $15 - $50
  • Fish Food: $5 - $20
  • Water Conditioner: $5 - $15

Mid-range setup (around $400 - $650):

  • Tank: 30-40 gallon aquarium with a lid or glass canopy ($60 - $120)
  • Filter: Canister filter or high-quality HOB filter rated for the tank size ($60 - $150)
  • Heater: 100-150 watt adjustable aquarium heater ($25 - $50)
  • Lighting: LED aquarium light with adjustable settings for plant growth and color enhancement ($50 - $150)
  • Substrate: Nutrient-rich aquarium substrate designed for planted tanks ($20 - $40)
  • Decor: A blend of driftwood, rocks, and live plants such as Amazon Swords, Java Fern, Anubias, and Cryptocoryne species ($40 - $80)
  • Fish: Minimum 5, maximum 15 Sailfin Mollies ($25 - $60)
  • Thermometer: $3 - $10
  • Substrate Vacuum: $10 - $25
  • Fish Net: $2 - $10
  • Algae Scraper or Magnetic Cleaner: $5 - $20
  • Siphon and Bucket: $15 - $30
  • Test Kit: $15 - $50
  • Fish Food: $5 - $20
  • Water Conditioner: $5 - $15

High-end setup (above $800):

  • Tank: 40-50 gallon rimless aquarium with a glass canopy ($120 - $250)
  • Filter: Premium canister filter rated for the tank size ($100 - $250)
  • Heater: 150-200 watt adjustable aquarium heater with an external temperature controller ($40 - $80)
  • Lighting: Advanced LED lighting system with customizable settings for plant growth, color enhancement, and day/night cycles ($150 - $300)
  • Substrate: Top-grade aquarium substrate designed for planted tanks, with supplementary root tabs for additional plant nutrition ($30 - $60)
  • Decor: An assortment of driftwood, rocks, and live plants to construct a natural aquascape, featuring plant varieties such as Amazon Swords, Java Fern, Anubias, Cryptocoryne species, and ground-covering plants like Dwarf Hairgrass or Monte Carlo ($60 - $150)
  • Fish: Minimum 5, maximum 20 Sailfin Mollies ($25 - $75)
  • Thermometer: $3 - $10
  • Substrate Vacuum: $10 - $25
  • Fish Net: $2 - $10
  • Algae Scraper or Magnetic Cleaner: $5 - $20
  • Siphon and Bucket: $15 - $30
  • Test Kit: $15 - $50
  • Fish Food: $5 - $20
  • Water Conditioner: $5 - $15

Do bear in mind that these figures are merely guidelines, and other aspects such as tank mates and individual fish personalities should be considered when deciding how many Sailfin Mollies to keep in your aquarium. Prices may vary depending on location, brand, and availability.

Set Up Your Tank

In the preceding sections, we outlined the ideal tank setups for your Sailfin Mollies and their potential tank mates. With a clear understanding of these requirements, it's time to delve into the stepwise procedure for preparing your aquarium. This guide will help you choose the best location for your tank, clean and prepare it for habitation, install the necessary equipment, and condition the water to create a healthy environment for your fish. Moreover, we'll discuss the right process for acclimating your Sailfin Mollies to ensure a stress-free transition to their new home. Adhering to these instructions will set you on the path to establishing a vibrant aquatic ecosystem where your fish can thrive.

  • Step #1: Begin by selecting an ideal location for your aquarium that's free from direct sunlight, heat sources, and cold drafts. Make sure the chosen spot is level and can bear the weight of a fully-loaded tank. If your aquarium needs a stand, set it up as per the manufacturer's guidelines, then place your empty tank on it.
  • Step #2: Proceed to clean the tank with fresh water, avoiding the use of soap or chemicals that might harm your fish. This step removes any dust or debris. Dry the inside of the tank using a clean cloth or paper towel. Thoroughly rinse your substrate (which could be sand or gravel) in a bucket until the runoff is clear. Spread the substrate evenly at the bottom of the tank, creating a gentle slope towards the back for aesthetic depth.
  • Step #3: Before introducing water to the tank, plan the layout of your aquarium, considering the positioning of equipment like heaters and filters. This planning stage will simplify future maintenance tasks. Install the heater and filter as per the manufacturer's instructions. If you've chosen a sponge or under-gravel filter, position it beneath the substrate prior to filling the tank with water.
  • Step #4: Adorn your tank with driftwood, rocks, and plants to provide hiding spots and create an appealing environment, while ensuring there are ample swimming areas for your Sailfin Mollies. Be mindful to arrange the decor in a manner that doesn't hinder or damage the equipment. To keep plants in place, you can anchor them to driftwood or rocks.
  • Step #5: Introduce water that's been treated with a water conditioner into the tank, particularly if your tap water contains chlorine or chloramines. Use a clean plate or plastic bag on the substrate to prevent disturbance while filling. Continue filling until the tank is about 2/3 full. Attach the aquarium light to the hood or canopy as per the manufacturer's instructions. Consider a timer for your aquarium light to ensure a consistent day/night cycle, crucial for the wellbeing of both fish and plants. Plug in the heater, filter, and any additional equipment (like an air pump or CO2 system), and install the thermometer where it can be easily read.
  • Step #6: Complete filling the tank, leaving some space between the water surface and the tank's top to facilitate oxygen exchange. Switch on the filter, heater, and other equipment, then adjust the water temperature with the heater, if required. Allow the tank to cycle for 4-6 weeks to develop beneficial bacteria and stabilize water parameters. During this cycling phase, adding a bacterial starter culture can expedite the growth of beneficial bacteria. Utilize an aquarium test kit to monitor levels of ammonia, nitrite, and nitrate.
  • Step #7: Once the tank is cycled and water parameters have stabilized, start introducing your Sailfin Mollies and other fish to the tank. Start by letting the unopened fish bag float in the tank for about 15-20 minutes to balance the temperatures. Then, open the bag and slowly add small amounts of tank water to it. Continue this process every 5-10 minutes for at least 30-60 minutes, allowing the fish to gradually adjust to the new water conditions. Using a net, gently transfer the fish from the bag to the tank, taking care not to stress the fish or introduce the bag water to your tank.
  • Step #8: Once all the fish have been transferred, set up a regular feeding schedule, offering quality food in suitable quantities for your fish species. Conduct regular water changes (20-30% every 1-2 weeks) and use a test kit to regularly monitor water parameters, ensuring a healthy environment for your fish. Keep a close eye on your fish for any signs of stress or disease, especially during the initial weeks after introduction. If needed, be ready to intervene, whether by adjusting water parameters or seeking help from a seasoned aquarist.

By following this comprehensive guide and implementing the extra setup tips, you'll be able to establish a prosperous aquatic habitat that will allow your Sailfin Mollies and other fish to thrive in their new environment.

Recommended Water Parameters

To ensure your Sailfin Mollies flourish, it is crucial to uphold certain water parameters in your aquarium. Here's a rundown of what to strive for:

  • Temperature: For the best results, keep the water within the range of 75°F and 82°F (24°C and 28°C).
  • pH: Maintain a neutral to slightly alkaline pH of 7.0 to 8.5, as they appreciate a bit of alkalinity.
  • Hardness: Hard water (20-30 dGH) is best suited for these fish, replicating their natural brackish water conditions.
  • Ammonia, Nitrite, and Nitrate: Ammonia and nitrite levels should always be at 0 ppm, while nitrate levels should be kept under 20 ppm.
  • Lighting: Moderate to bright lighting is fine, though they appreciate places to hide and seek shade.
  • Water movement: Moderate to strong water movement is preferable, simulating their natural coastal habitats.Consistently test your aquarium water and perform the necessary water changes to keep the conditions stable.

Routine Water Maintenance

Frequent water changes are essential for a healthy Sailfin Molly tank. They help eliminate excess nutrients, waste, and toxins. Here's a suggested protocol:

  • Weekly water changes: Refresh 25-30% of the tank water weekly.
  • Test water parameters: Regularly check pH, ammonia, nitrite, nitrate, and hardness.
  • Use a gravel vacuum: Employ this tool to clean the substrate during water changes.
  • Dechlorinate the water: Pre-treat tap water with a water conditioner before introducing it to the tank.
  • Match temperature and pH: Ensure the new water is similar in these aspects to the tank water.
  • Acclimate the fish: Allow your fish time to adjust to the new conditions post water changes.

In addition to routine water maintenance, consider the following to ensure your fish's health and the overall aesthetics of your aquarium:

  • Monitor lighting duration: Maintain a consistent 10-12 hour photoperiod, being mindful that excessive light could lead to algae overgrowth.
  • Plant maintenance: Regularly prune live plants to keep them healthy and attractive. Remove any dead foliage or plant matter to avert water quality issues.
  • Filter maintenance: Clean or replace the filter media as suggested by the manufacturer, typically every 4-6 weeks. Be cautious not to replace all filter media simultaneously as it can disturb the beneficial bacteria and cause water quality problems.

Diet and Feeding Schedule

Sailfin Mollies are primarily herbivores but will enjoy some animal-based foods. Here are some feeding tips:

  • Flakes and pellets: Utilize high-quality flake or pellet food specifically designed for mollies.
  • Algae and vegetables: Offer algae wafers and blanched vegetables, such as peas, lettuce, or zucchini.
  • Occasional meaty foods: Offer treats of brine shrimp or bloodworms sparingly.
  • Feeding frequency: Feed small portions once or twice a day, making sure to avoid overfeeding.

Stress and Diseases

Sailfin Mollies can experience stress from various sources, such as poor water quality, hostility, or unsuitable tank conditions. Identifying and addressing these stressors is crucial for your fish's health:

  • Watch for stress signs: Be vigilant for unusual behaviors like hiding, lethargy, color loss, or rapid breathing, which could indicate stress.
  • Check water quality: Test your aquarium water to ensure it meets the ideal parameters, and conduct regular water changes to uphold a healthy environment.
  • Monitor tank mates: Ensure your Sailfin Mollies aren't being bullied or attacked by other fish and remove any aggressive tank mates if necessary.
  • Create a suitable habitat: Offer ample hiding spots, appropriate lighting, and an adequately sized tank for your fish.

While Sailfin Mollies are relatively robust, they can still succumb to common fish diseases, such as:

  • Ich (white spot disease): This widespread parasitic infection causes white spots on the body and fins, lethargy, and loss of appetite. You can treat Ich with aquarium salt or anti-parasitic medication and raise the water temperature slightly.
  • Fin rot: A bacterial infection resulting in frayed or discolored fins and tail. Treat fin rot with a partial water change, aquarium salt, and antibacterial medication.
  • Livebearer Disease (Shimmies): A condition characterized by erratic swimming, like shaking or shimmying. This is usually a sign of stress or poor water conditions, so check your water parameters and make any necessary adjustments.
  • Fungal infections: Fungus can affect Sailfin Mollies, causing cottony growths on the body. You can treat fungal infections with antifungal medication.

Prevent diseases in Sailfin Mollies by maintaining excellent water quality, avoiding overfeeding, and providing a balanced diet. Quarantine new fish before introducing them to the main tank and promptly address any signs of illness.


Breeding Sailfin Mollies can be an exciting endeavor, and it's generally easier than breeding many other types of fish. Here are the steps to breed Sailfin Mollies:

  • Step #1: Establish an appropriate breeding environment in a separate 20-gallon or larger breeding tank, a pH level of around 7.5 to 8.5, and a temperature of about 78°F (26°C). Maintain hard water (20-30 dGH) and include live plants for the fish's comfort.
  • Step #2: Choose healthy, mature male and female Sailfin Mollies for breeding. Maintain a ratio of two females to one male to prevent the males from stressing a single female. You can determine the gender by observing their physical characteristics.
  • Step #3: Ensure the breeding mollies have a high-quality diet, rich in vegetable matter, to help them build strength and energy.
  • Step #4: Introduce the pair to the breeding tank, providing plenty of hiding spots for the female to escape if the male becomes too aggressive.
  • Step #5: Care for the fry by providing them with a high-quality diet, starting with crushed flake food or specially designed fry food. Since mollies are livebearers, there will be no eggs to care for.
  • Step #6: Monitor the growth and development of the fry, and separate them by size if necessary to prevent larger fry from preying on smaller ones.

Breeding Sailfin Mollies can be a rewarding experience for both novice and experienced aquarists. Patience and the right conditions are key to success.

Recommended Tank Mates

Here are the top 10 recommended tank mates for Sailfin Mollies:

  • Platies
  • Guppies
  • Swordtails
  • Tetras
  • Ghost Shrimp
  • Apple Snails
  • Other Mollies
  • Corydoras Catfish
  • Harlequin Rasboras
  • Cherry Barbs

Avoid housing Sailfin Mollies with aggressive or larger predatory fish such as cichlids or angelfish, as they may pose a threat. Always monitor the behavior of any new additions to the tank to ensure they aren't causing stress or aggression towards the Sailfin Mollies.


In essence, Sailfin Mollies are a popular freshwater fish species, adored for their elaborate fins and ease of care. These fish require specific water conditions, a balanced diet, and a suitable environment to flourish. With proper care, they can live up to five years and make a great addition to any community tank. Choosing peaceful and non-aggressive tank mates is crucial to maintain harmony. Breeding Sailfin Mollies can be a rewarding experience, albeit a bit challenging for beginners, but with patience and ideal conditions, success is within reach. All in all, Sailfin Mollies are an attractive and lively species that can enhance the aesthetics and dynamics of any home aquarium.

Frequently Asked Questions

What is the ideal tank size for Sailfin Mollies?

Sailfin Mollies are larger than many other livebearers, and for a small group, a 30-gallon tank is the minimum recommended size. A larger tank can help maintain stable water conditions and provide sufficient space for your fish.

How many Sailfin Mollies should be kept together?

Sailfin Mollies are sociable creatures and do well in groups. It's best to keep them in groups of at least five individuals to ensure they feel safe and can exhibit their natural behaviors.

What water parameters do Sailfin Mollies require?

Sailfin Mollies prefer slightly alkaline water with a pH of 7.5-8.5, a temperature range of 72°F to 82°F (22°C to 28°C), and moderately hard to hard water (15-30 dGH).

What do Sailfin Mollies eat?

Sailfin Mollies are omnivores with a preference for plant matter. Feed them a mix of high-quality flake food, algae wafers, and occasional live or frozen foods like brine shrimp or daphnia.

Are Sailfin Mollies compatible with other fish?

Yes, Sailfin Mollies are generally peaceful and can coexist with other similar-sized, non-aggressive fish species. Ideal tank mates include platies, guppies, and corydoras catfish.

How can I differentiate between male and female Sailfin Mollies?

Male Sailfin Mollies have a modified anal fin, known as a gonopodium, which is used for breeding. Females have a standard, fan-shaped anal fin. Also, males have larger, more prominent dorsal fins.

How long do Sailfin Mollies live?

With optimal care and suitable tank conditions, Sailfin Mollies can live for up to 5 years.

How do I breed Sailfin Mollies?

Breeding Sailfin Mollies requires a separate breeding tank with slightly hard, alkaline water. The males and females should be well-fed and healthy before introducing them for spawning.

Do Sailfin Mollies require a planted tank?

While not strictly required, a planted tank is beneficial for Sailfin Mollies. Live plants offer hiding spots, contribute to water quality, and simulate a more natural environment that mirrors their wild habitats.

Can Sailfin Mollies change color?

Yes, Sailfin Mollies can undergo color changes due to various factors such as stress, disease, or shifts in water conditions. If you notice a change in your Sailfin Mollies' color, it's crucial to check the water parameters and monitor their health closely.