Swordtail Fish Care Guide

Swordtail fish (Xiphophorous hellerii) are a very popular community aquarium fish. Their popularity stems from their ease of care and peaceful nature. They have quite unique types of fins with a great variety of colors, making them commonly referred to as Red swordtails or Green swordtails. Today, they are bred to achieve various colors and, as a result, great deals of different types exist.

Swordtail Fish

In the wild, swordtails usually have olive green bodies with a red stripe that stretches along the body. Their natural habitat is in Central America and North America, where they were discovered in 1848. Swordtail fish are average size freshwater species; males are typically slightly smaller than females (6.3 inches) and they reach 5.5 inches maximum. They live in groups, but are not a schooling fish. One of the things that make them so popular is their hardiness, as they can survive in very diverse environments.

Whether you plan to keep them as a single aquarium species or in a community aquarium, you should know their general needs.


Swordtail fish are average-size fish; they don’t need very much space due to their size, but given they are very active, they greatly benefit from having enough space to swim around. The minimum tank size for one adult swordtail fish should be at least 15-gallons. However, if you plan to add other fish for good company, plan to house them in at least a 29-gallon aquarium. The best male to female ratio is one male and three or four females. In this way, males won’t overly harass the females, as harassment will be evenly distributed. Swordtails are great jumpers so consider covering your aquarium in order to prevent possible suicide attempts.

Water parameters

Swordtail fish are sturdy tropical fish that can tolerate a wide range of water temperatures. They should do fine in any water temperature between 65- 82⁰Fahrenheit. Even though they are adaptable and quite durable, avoid sudden and violent temperature drops in temperature, as this can harm your fish and make their immune system vulnerable.

Swordtail prefer very hard water from 12–30 dGH and an ideal water pH anywhere between 7.0 and 8.4. In general, they prefer moderately alkaline, hard water.

Always take care that your water is properly filtrated. If you set your filtration system right, the water parameters will stay strong. Always keep track of water parameters so you can react and prevent possible complications. Your fish will then happily thrive and live to full potential.


Swordtail fish will accept a wide variety of foods. You can give them quality flake food or live foods like bloodworms, daphnia, brine shrimp, mosquito larvae, or fruit flies, as they will eat virtually anything.

Swordtail fish eat a lot of algae and other vegetation in their natural habitat. Don’t neglect their need for proper herbivorous food. Make sure to give them an ideal mix of protein and vegetation in order to perfectly satisfy their exact diet needs.

Swordtail Fish

Tank mates

Swordtail fish are a peaceful and active species. They are very social and enjoy good company, especially when housed with other swordtails or similar passive species. The swordtail fish can make a great companion in similar cousins, such as platies, mollies, or angelfish. Peaceful types of corydoras are also great as their companions. Some larger types of tetras can be great, too, but keep them in schools of five or more to prevent possible harassment.

Male swordtail fish are almost always aggressive towards other males of the same species. If your tank isn’t huge, you should definitely opt to keep only one male along with two or three females in one tank.


As livebearers, the swordtail fish are great at breeding efficiently and very quickly, without any intervention from the aquarist. Once a swordtail female has been impregnated, you should clearly see a huge belly with a dark gravid spot near the anal fin.

Once the fry are born, you should take some protective measures in order to keep them alive otherwise they will be consumed by their parents or other tank mates. You can do this either by adding more plants that will serve as hiding spots for young fry or by physically removing adults (or fry for that matter) from the tank.

The latter is much more efficient, as only some of the young will survive if they are not separated from the adults. When the fry become large enough not to be viewed as food by adults, gently introduce them to your tank.

11 thoughts on “Swordtail Fish Care Guide”

  1. Well now that I have 2 sword tail fish, I have been learning a lot about them, however, how well would it work if I were to have say like 5 or 6 female sword tail fish with the 2 male swordtail fish that I have already?

  2. The common and best ratio is 1 male to 3 or 4 female fish so 2 males with 6 female fish would be Judy fine if you take care of them all right.

    • It will depend on your tank size. For a community like that you are going to want at least 25 gallons. The more space you have the better you will do.

  3. 1 female 1 male the female died male has tail fun & little more tail fun gone and top fun discolored. Tanks only 5 weeks old, 10 gal and with 2 female guppies and female & male mollies. All others look fine.

    • You need to keep at least 3 females per male. I have made this mistake before as well. Your male is probably damaged by the female as they will nip each other if they are harassed too much.

  4. We have 7 to say tetra , 2 small Angel fish
    size of 10p piece. We did a partial water change, cleaned plants off in some syphoned tank water. Our tank has been up and running for about 8weeks. We were told by the arquiruim shop our external tank will need cleaning in about 3 months with it being new.
    We few days ago introduced 4 small swordfish
    1 male to 3 females. Plus 3 full grown ones 1 male to 2 females. Second and day of new arrivals we lost 1 tetra, 2 days later we lost the bigger male sword fish and today woke up to find another tetra has died. Worring over the larger female sword fish had around the mouth looks like either been bitten or some sort of infection. It has white fleshy type material hanging from the lip area. The fish is swimming ok likes to rest in the gravel seems bit quiet around feeding time with the other fish who are quiet greedy. Any advice would be most welcome.


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