Marigold Swordtail

Marigold Swordtails are fascinating freshwater fish related to other Swordtails and Platies. With their distinctive marigold orange colors, they've garnered a following among aquarium hobbyists. These friendly fish require basic upkeep, making them an excellent pick for community aquariums.

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Care DIfficulty


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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 Marigold Swordtail, scientifically known as Xiphophorus hellerii, often referred to as the Orange Swordtail, is a popular freshwater fish originating from Central America, primarily Mexico and Honduras. They are typically found in fast-moving streams and rivers in their natural habitat.

In the wild, Marigold Swordtails inhabit areas with plenty of vegetation and prefer shallow, clear waters. These plants provide shelter and also function as a food source, while the clear streams enhance their vibrant colors. These sociable fish flourish in groups, although they're not as schooling oriented as tetras.

Their native habitat includes temperate to warm water. The temperature typically ranges from 72 to 78 degrees Fahrenheit (22 to 26 degrees Celsius), with a pH level of 7.0 to 8.3, and water hardness between 12 to 30 dGH. To emulate a similar environment in your aquarium, ensure a steady water temperature, implement a high-quality filtration system, and include live plants and rocks.

By replicating the Marigold Swordtail's natural habitat and maintaining the right water parameters, you'll facilitate a healthy and content life for your fish in your aquarium.

Marigold Swordtails are known for their radiant marigold orange coloration, paired with a unique, elongated lower caudal fin, or 'sword.' These dazzling colors make them an enticing and noteworthy addition to aquariums. Despite their small size, growing up to approximately 4 inches (10 cm) in length, their bright colors and playful demeanor make them a perfect choice for those desiring a lively, vibrant aquatic display. These delightful fish captivate observers as they energetically dart around the tank, making them a treasured favorite among hobbyists across the board.

With careful care, Marigold Swordtails can live up to five years. As sociable creatures, they thrive in groups and do well when kept with a mix of male and female individuals. To enhance their well-being and ensure longevity in captivity, it's crucial to provide an aquarium rich in plants with ample hiding spaces, and a varied diet comprising quality flakes, pellets, and occasional live foods.

Fun Facts

Now that we've familiarized ourselves with the appearance and lifespan of Marigold Swordtails, we're moving on to some engaging trivia about these stunning fish. From their unique morphology to their social behavior, Marigold Swordtails are filled with captivating features that attract aquarium enthusiasts.

  • Adaptation for reproduction: In the wild, Marigold Swordtails are known to display a unique survival strategy. Males of this species have a modified anal fin known as a 'gonopodium' that facilitates internal fertilization, providing a survival edge in fast-moving water environments where external fertilization might prove challenging.
  • Sexual dimorphism: Unlike many fish species, Marigold Swordtails exhibit clear sexual dimorphism, meaning males and females of the species can be easily distinguished. Notably, only the males boast the namesake 'sword'—an elongated lower fin—whereas the females do not have this feature.
  • Color change with age: Marigold Swordtails exhibit an interesting phenomenon related to their coloration. As they age, their striking marigold color can intensify, providing a captivating display in your home aquarium as they mature.
  • Flexibility in diet: One notable feature of Marigold Swordtails is their omnivorous diet. This means that they can consume both plant and animal matter, making them flexible and easy to care for in an aquarium setting.
  • Live-bearers: A fun fact about Marigold Swordtails is that they're live-bearers. Instead of laying eggs, females give birth to live young, adding an exciting dynamic to your aquarium when they breed.

After discovering these interesting facts about Marigold Swordtails, you'll be better equipped to appreciate their intricacies and beauty in your aquarium. In the next section, we'll give advice on tank setups, ensuring your Marigold Swordtails have a perfect environment to thrive and flaunt their stunning features.

Recommended Tank Setups

These setups include essential components such as the tank, filter, heater, lighting, substrate, and more, providing an ideal environment for Marigold Swordtails and other suitable freshwater fish species in your aquarium. As we transition from cost-effective to premium setups, you'll find an array of choices for personalization, aesthetic appeal, and superior features. Marigold Swordtails are social fish that thrive in groups, with at least five individuals recommended for optimal well-being. Marigold Swordtails typically cost between $3 and $5 per fish, although prices can fluctuate based on size, quality, and availability.

Budget-friendly setup (around $200):

  • Tank: 20-gallon aquarium with a hood or glass canopy‍ ($40 - $70)
  • Filter: Hang-on-back (HOB) or sponge filter suitable for 20 gallons ($20 - $40)
  • Heater: 50-100 watt adjustable aquarium heater ($15 - $30)
  • Lighting: Basic LED aquarium light ($20 - $50)
  • Substrate: Cost-effective aquarium sand or small gravel ($10 - $20)
  • Decor: Several pieces of driftwood and rocks, supplemented with budget-friendly live plants such as Java Fern and Anubias ($20 - $40)
  • Fish: Minimum 5, maximum 10 Marigold Swordtails ($15 - $25)
  • 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-gallon aquarium with a hood or glass canopy ($60 - $120)
  • Filter: Canister filter or high-quality HOB filter designed for the tank size ($60 - $150)
  • Heater: 100-150 watt adjustable aquarium heater ($25 - $50)
  • Lighting: LED aquarium light with adjustable brightness for plant growth and color enhancement ($50 - $150)
  • Substrate: Nutrient-rich aquarium substrate created for planted tanks ($20 - $40)
  • Decor: A variety of driftwood, rocks, and live plants such as Amazon Swords, Java Fern, Anubias, and Cryptocoryne species ($40 - $80)
  • Fish: Minimum 5, maximum 15 Marigold Swordtails ($25 - $50)
  • 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-gallon rimless aquarium with a glass canopy ($120 - $250)
  • Filter: Superior canister filter designed 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-quality aquarium substrate designed for planted tanks, with added root tabs for extra plant nutrition ($30 - $60)
  • Decor: An assortment of driftwood, rocks, and live plants for a natural aquascape, featuring plant species such as Amazon Swords, Java Fern, Anubias, Cryptocoryne species, and carpeting plants like Dwarf Hairgrass or Monte Carlo ($60 - $150)
  • Fish: Minimum 5, maximum 20 Marigold Swordtails ($25 - $70)
  • 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

Remember, these suggestions are general guidelines, and you should consider other variables like potential tank mates and the distinct personality of individual fish when deciding the number of Marigold Swordtails for your aquarium. Prices might vary based on location, brand, and availability.

Set Up Your Tank

The preceding section outlined ideal tank setups for your Marigold Swordtails and other compatible species. With that knowledge, let's navigate the hands-on process of preparing your aquarium. We'll cover crucial steps like choosing the best spot for your tank, cleaning procedures, installation of essential equipment, and preparing the water through cycling. We'll also delve into the correct way to acclimate your Marigold Swordtails to minimize stress. Follow these instructions, and you'll be on the path to fostering a successful aquatic ecosystem for your Marigold Swordtails and their tank mates.

  • Step #1: Pick the right location for your aquarium. It should be free from direct sunlight, away from drafts, and clear of heat sources. Ensure the spot is level and can bear the weight of your filled tank. If your setup involves a stand, set it up as per the manufacturer's guidelines and then place your empty tank on it.
  • Step #2: Clean the tank using clean, non-soapy water to remove any dust or residues. Use a clean cloth or paper towel to wipe the interior. Thoroughly rinse the substrate in a bucket until water runs clear. Then, distribute it evenly across the tank's base, sculpting a gentle slope towards the rear for an added sense of depth.
  • Step #3: Plan the layout of your aquarium, considering equipment placements like heaters and filters before filling the tank. This will streamline the setup and future maintenance. Fix the heater and filter according to the manufacturer's instructions. If you're opting for a sponge or under-gravel filter, install it beneath the substrate before pouring in water.
  • Step #4: Embellish the tank with driftwood, rocks, and plants, fostering natural hideouts and enhancing visual appeal. Ensure open swimming spaces are left for your Marigold Swordtails. While decorating, make sure that the equipment isn't hindered or damaged. Consider fastening plants to driftwood or rocks for better stability.
  • Step #5: Fill the tank with chlorine-free or dechlorinated water. To prevent disrupting the substrate while filling, place a clean plate or plastic bag on it. Fill about two-thirds of the tank, then fix the aquarium light on the hood or canopy, adhering to the manufacturer's guidelines. A timer might be beneficial to keep a consistent day-night cycle, important for both plants and fish. Connect the heater, filter, and any additional equipment like air pumps or CO2 systems to the power source. Finally, install the thermometer in a place that's easily visible.
  • Step #6: Complete filling the tank, leaving some space between the water surface and the top of the tank for oxygen exchange. Turn on the filter, heater, and other equipment. Regulate the water temperature, adjusting the heater as necessary. Let the tank cycle for 4-6 weeks to cultivate beneficial bacteria and balance water parameters. You can quicken the establishment of beneficial bacteria by adding a bacterial starter culture during the cycling process. Regularly monitor ammonia, nitrite, and nitrate levels using a test kit.
  • Step #7: After the cycling process is complete and water parameters are stable, acclimate your Marigold Swordtails to the tank's conditions. Start by floating the sealed fish bag in the tank for 15-20 minutes to equate the temperatures. Then, gradually add small amounts of tank water to the bag every 5-10 minutes for about half to one hour. This gradual introduction will let the fish adjust to the new water chemistry. Carefully transfer the fish from the bag to the tank with a net, minimizing stress and avoiding any introduction of bag water into the tank.
  • Step #8: Once all the fish are in, set a consistent feeding routine, offering the appropriate quantity of quality food for your fish species. Conduct regular water changes (20-30% every 1-2 weeks) and use a test kit to monitor water parameters to maintain a healthy environment. Keep an eye on your fish for signs of stress or disease, particularly in the first few weeks. Be ready to intervene as necessary, such as adjusting water parameters or consulting an experienced aquarist.

By adhering to this guide and embracing the additional setup tips, you can provide a dynamic aquatic habitat that allows your Marigold Swordtails and other species to thrive.

Recommended Water Parameters

The health and vibrancy of your Marigold Swordtails are largely influenced by maintaining specific water conditions in your aquarium. Here are the ideal parameters:

  • Temperature: The optimal water temperature for these fish should range from 72°F to 78°F (22°C to 25°C).
  • pH: Marigold Swordtails prefer slightly alkaline water, with a pH level between 7.0 and 8.3.
  • Hardness: Moderately hard to hard water, around 12-30 dGH, suits these species best.
  • Ammonia, Nitrite, and Nitrate: Aim for 0 ppm for both ammonia and nitrite. Keep nitrate concentrations as low as possible, ideally under 20 ppm.
  • Lighting: Moderate lighting conditions are well tolerated by Marigold Swordtails.
  • Water movement: Moderate water flow that mimics their natural environment is ideal for these fish.

Regular testing and water changes can help maintain these conditions in your aquarium.

Routine Water Maintenance

Maintaining high water quality is crucial for a thriving Marigold Swordtail tank. Here are some key maintenance tasks:

  • Weekly water changes: Replace about 25-30% of the aquarium water weekly.
  • Test water parameters: Regularly check levels of pH, ammonia, nitrite, nitrate, and hardness.
  • Use a gravel vacuum: Employ a gravel vacuum during water changes to keep the substrate clean.
  • Dechlorinate the water: Always treat tap water with a suitable water conditioner before introducing it to your tank.
  • Match temperature and pH: The newly added water should have a similar temperature and pH to the existing tank water.
  • Acclimate the fish: Allow your Marigold Swordtails enough time to adjust to new water conditions after water changes.In addition to routine maintenance, here are additional tips to keep your aquarium in top shape:
  • Monitor lighting duration: Maintain a consistent photoperiod of about 8-12 hours each day to discourage excessive algae growth.
  • Plant maintenance: Trim live plants regularly and promptly remove any dead plant matter to avoid water quality degradation.
  • Filter maintenance: Follow the manufacturer's instructions for cleaning or replacing the filter media, typically every 4-6 weeks, and avoid changing all filter media at once to preserve beneficial bacteria.

Diet and Feeding Schedule

Marigold Swordtails are omnivores, requiring a varied diet for optimal health. Here are the feeding essentials:

  • Flakes and pellets: High-quality flake food or pellet food is the core of their diet.
  • Frozen and live foods: Daphnia, brine shrimp, and bloodworms can serve as occasional treats.
  • Vegetable matter: Small amounts of blanched vegetables like peas, zucchini, and spinach provide added nutrients.
  • Feeding frequency: Feed your fish twice a day, giving only the amount they can consume in a few minutes to avoid overfeeding.

Stress and Diseases

Like any fish, Marigold Swordtails can become stressed due to poor water quality, inappropriate tank conditions, or aggressive tank mates. Identifying and mitigating these stressors is crucial:

  • Watch for stress signs: Observing your Marigold Swordtails for signs like hiding, rapid breathing, color loss, or lethargy can alert you to potential issues.
  • Check water quality: Regularly test your aquarium water and make necessary adjustments to maintain ideal parameters.
  • Monitor tank mates: Ensure that your Marigold Swordtails are not being bullied by other fish, and rehome any overly aggressive species.
  • Create a suitable habitat: Ensure your aquarium has ample swimming space, hideouts, and proper lighting to support your fish.

Marigold Swordtails, although robust, can succumb to common fish diseases such as:

  • Ich (white spot disease): A common parasitic disease recognizable by white spots on the body and fins. Raise the water temperature gradually to around 82°F (28°C) and administer anti-parasitic treatment.
  • Fin rot: A bacterial infection causing frayed, discolored fins and tail. Partial water changes, antibacterial medication, and maintaining water quality can help treat fin rot.
  • Velvet disease: A parasitic condition indicated by a velvet-like coating on the fish's body. Copper sulfate or formalin-based medications can be used for treatment.
  • Swim bladder disease: Symptoms include swimming issues like floating or sinking, and it can be managed with a fast followed by a diet of blanched peas.

Prevention is the best cure, achieved by maintaining high water quality, balanced diet, and quarantining new fish before adding them to the main tank.


Breeding Marigold Swordtails is relatively straightforward with the correct environment and conditions. Follow these steps:

  • Step #1: Establish a suitable breeding space with a separate tank, keeping pH levels between 7.0 and 8.3, a temperature around 77°F (25°C), and provide plenty of plant cover for egg-laying.
  • Step #2: Select healthy adult Marigold Swordtails for breeding. Usually, one male to two or three females is a good ratio to prevent the male from harassing a single female.
  • Step #3: Condition the breeding pair with a nutritious diet of live and vegetable foods to promote egg production.
  • Step #4: Male swordtails will chase females for mating. After mating, female swordtails carry the eggs inside them until they hatch, which can take around 4 to 6 weeks.
  • Step #5: Once the fry are born, remove the adult fish to prevent them from eating the young. Initially feed the fry with infusoria or liquid fry food and later introduce crushed flake food.
  • Step #6: Observe the fry's growth, and when large enough, they can be introduced to the main tank.

With patience and optimal conditions, breeding Marigold Swordtails can be an enjoyable part of the aquarium hobby.

Recommended Tank Mates

Consider these top 10 suitable tank mates for Marigold Swordtails:

  1. Molly Fish
  2. Platies
  3. Tetras
  4. Gouramis
  5. Corydoras Catfish
  6. Ghost Shrimp
  7. Zebra Danios
  8. Mystery Snails
  9. Cherry Barbs
  10. Harlequin Rasboras

Steer clear from large, aggressive species like cichlids and predatory fish, as they might bully or harm the Marigold Swordtails. Always monitor the behavior of new fish to ensure they don't exhibit aggression towards the Marigold Swordtails.


In a nutshell, Marigold Swordtails are an enchanting species of freshwater fish, known for their striking colors and relatively easy care. These fish require specific water conditions, a balanced diet, and a suitable environment to flourish in captivity. With proper care, they can live up to three to five years and make a delightful addition to any home aquarium. When choosing tank mates, it's essential to pick peaceful and non-aggressive species to maintain a harmonious community. Breeding Marigold Swordtails is typically a straightforward process, particularly under ideal conditions. Overall, Marigold Swordtails are a lively and visually stunning species that can brighten any aquarium with their vibrant colors and active behavior.

Frequently Asked Questions

What is the ideal tank size for Marigold Swordtails?

A 30-gallon tank is the minimum recommended size for Marigold Swordtails. A larger tank provides better stability in water conditions and gives these active swimmers plenty of space.

How many Marigold Swordtails should be kept together?

Marigold Swordtails are social fish that do well in small groups. To ensure gender balance and reduce aggression, aim for a ratio of one male to two or three females.

What water parameters do Marigold Swordtails require?

Marigold Swordtails prefer water temperatures between 72°F and 78°F (22°C and 25°C), a pH between 7.0 and 8.3, and moderately hard to hard water with a hardness between 12 and 30 dGH.

What do Marigold Swordtails eat?

Marigold Swordtails are omnivores and enjoy a diverse diet. Feed them a mix of high-quality flake or pellet food, supplemented with live or frozen foods like brine shrimp and bloodworms, as well as some vegetable matter.

Are Marigold Swordtails compatible with other fish?

Yes, Marigold Swordtails are generally peaceful and can live harmoniously with other similarly sized, non-aggressive species. Suitable tank mates include mollies, platies, tetras, and small catfish species.

How can I differentiate between male and female Marigold Swordtails?

Male Marigold Swordtails have a long, sword-like extension on the lower edge of their tail, which females lack. Males also tend to be more vibrantly colored.

How long do Marigold Swordtails live?

With optimal care and tank conditions, Marigold Swordtails can live for 3 to 5 years.

How do I breed Marigold Swordtails?

Breeding Marigold Swordtails is relatively straightforward under suitable conditions. Use a separate breeding tank with a male to female ratio of 1:2 or 1:3. After mating, the female will carry the eggs inside her until they hatch, which typically takes around 4 to 6 weeks.

Do Marigold Swordtails require a planted tank?

Although not absolutely necessary, a planted tank is beneficial for Marigold Swordtails. Live plants offer hiding spots, help maintain water quality, and create a more natural, comfortable environment.

Can Marigold Swordtails change color?

Yes, Marigold Swordtails can experience color changes due to various factors such as stress, illness, or changes in water conditions. If you notice your Marigold Swordtails displaying color loss, it's crucial to check the water parameters and monitor their health closely.