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Swordtail Care Sheet

Developed with and approved by a qualified veterinarian.

Swordtail Fish

This care sheet covers a variety of swordtail species, including:   



Scientific name: Xiphophorus hellerii

Swordtails come in a wide variety of colors and are most recognizable by the male’s long sword-like lower caudal fin. They are peaceful freshwater livebearers that originate in North, Central or South America. They give birth to live young and can rapidly reproduce. Swordtails thrive in strong flowing water but can readily adapt to changes in water conditions, making them recommended fish for beginning aquarists.


Typical appearance and behavior 

  • Females are typically larger  than their male counterparts
  • Swordtails come in many varieties and a large array of colors and patterns
  • Swordtails are easy to care for and flourish in groups of three or more of the same species
  • Although not a schooling species, they are generally social and peaceful and prefer the company of other swordtails
  • Males can become territorial and aggressive toward each other if females do not outnumber the males in the aquarium 



Care Difficuty Beginner
Average Life Span Up to 5 years with proper care
Average Adult Size Up to 6 inches long
Diet Omnivore
Minimum Habitat Size 10+ gallons, depending on species
Water Temperature 72-82°F



Habitat size

Keep in an appropriate size aquarium based on the species selected, which can range from 10 gallons for a couple swordtails to a much larger aquarium for a school of swordtails.

Building your habitat

  • Water health - Provide proper filtration to ensure optimal water quality to help maintain health. Moderate to strong water circulation should be provided to mimic water currents and high oxygen levels found in a swordtail’s natural habitat. Stable water quality (pH, ammonia, nitrate, nitrite) and water temperature are critical to the health of aquatic life. If you are unsure of your water quality, bring a sample to Petco for free testing. An aquatic heater should be used to stabilize water temperature, ensuring it does not fluctuate more than 2 degrees in either direction in a 24-hour period. Many swordtails will benefit from the addition of freshwater salt to the aquarium; the specific gravity should be kept at 1.004. Always research your species-specific needs before adding freshwater aquarium salt. Do not allow specific gravity to fluctuate more than 0.001 in either direction in a 24-hour period
  • Decor - Provide plenty of space for swimming, as well as plants, rocks or decor for hiding places



A well-balanced swordtail diet consists of:

  • Food may be flakes, pellets, freeze-dried or frozen
  • Offer a varied diet to ensure it is nutritionally complete

Things to remember when feeding your swordtail:

  • Depending on species and size, feed small amounts 1-3 times daily, no more than fish will eat in 1-2 minutes
  • Thaw frozen food before feeding


Swordtail care

  • Water care: Maintaining great water quality with regular water changes and adequate filtration is important to help keep your swordtail healthy
    • Daily: Check filter, water temperature and other equipment
    • Weekly: Test water quality at least once a week
    • Weekly to monthly: Change 10–25% of the total volume of water every 2–4 weeks, or as needed; change filter media monthly
  • Avoid overcrowded conditions; they are a major cause of stress and disease 


Where to buy swordtails

Swordtails are available for purchase at Petco online and in-store; availability varies by location. If visiting your local location, please call ahead to check availability.




Tank mates 

  • Swordtails do well in most community aquariums with fish like:
    • Mollies
    • Guppies
    • Platys
    • Gouramis
    • Tetras
    • Rasboras
    • Rainbowfish
    • Dainos
    • Cory catfish 
  • Introduce new inhabitants to the aquarium gradually



Signs of a healthy swordtail

  • Clear eyes
  • Healthy appetite
  • Bright, even coloring
  • Clean in appearance
  • Free of parasites or disease

Red flags (If you notice any of these signs, contact your local aquatic specialist or aquatic veterinarian)

  • Loss of color or appetite
  • Spots or fungus on body or mouth
  • Erratic swimming
  • Frayed fins
  • Weight loss
  • Bloating
  • Cloudy eyes or pop-eye
  • Loss of appetite
  • Listlessness


Common swordtail health issues

Health Issue Symptoms or Causes Suggested Action
Health IssueFin rot Symptoms or CausesFrayed or disintegrating fins; the base of the fins usually reddens. Suggested ActionImprove water quality; consult your local aquatic specialist or aquatic veterinarian for treatment.
Health IssueIch Symptoms or CausesWhite spots appear on fins and body; fish rubs against hard objects or swims erratically; rapid respirations. Suggested ActionQuarantine fish immediately; add freshwater salt and use a commercial ich remedy as directed;. consult your local aquatic specialist or aquatic veterinarian for treatment.
Health IssueFungus Symptoms or CausesWhite cottony growth and/or discoloration of the eyes. Suggested ActionQuarantine fish; use a commercial antifungal remedy as directed; consult your local aquatic specialist or aquatic veterinarian for treatment.
Health IssueBacterial infections Symptoms or CausesCloudy eyes, open sores and/or reddening of the skin. Suggested ActionImprove water quality; add freshwater aquarium salt; use a commercial antibacterial remedy as directed; consult your local aquatic specialist or aquatic veterinarian for treatment.
Health IssueCottonmouth or columnaris Symptoms or CausesCottony white growths along the body and/or gills, frayed fins and gills turn brown and necrotic in late stages; caused by bacterial infection. Suggested ActionQuarantine fish; improve water quality; lower aquarium temperature to 72°F to deter bacteria from growing; medicate as directed; consult your local aquatic specialist or aquatic veterinarian for treatment.



  • How big do swordtails get? Swordtails can grow up to 6 inches; females tend to grow larger than their male counterparts.
  • What fish can live with a swordtail? Swordtails are a peaceful community fish and typically live well with species like mollies, platys, tetras and other peaceful community fish species. 
  • What do swordtail fish eat? Swordtails can be offered a varied diet of flakes, pellets, freeze-dried or frozen foods.  


Additional care sheets

Notes and resources

Ask a Pet Care Center partner about Petco's selection of products available for the care and happiness of your new pet. All products carry a 100% money-back guarantee.

Because all aquatic life are potential carriers of infectious diseases, such as  atypical mycobacterium and salmonella, always wash your hands before and after handling your aquatic life and/or habitat contents to help prevent the potential spread of diseases.

Pregnant women, children under the age of 5, senior citizens and people with weakened immune systems should contact their physician before purchasing and/or caring for aquatic life and should consider not having aquatic life as a pet.

Go to the Centers for Disease Control at for more information about aquatic life and disease.

The information on this care sheet is not a substitute for veterinary care. If you need additional information, please contact your veterinarian as appropriate.