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Xiphophorus Introduction 

A small tank may fit in your office or room space, but what amazing fish can fit into it? It could be the best candidate. With only 14-16cm and an adorable appearance, these fish would make your small-medium aquarium stand out. Unlike territorial fish, these Xipho fish can swim around the tank, pampering every pair of eyes enjoying them.

They or swordtail fish are stunning species native to North and Central America as well as, Africa, and parts of Mexico. They can survive in a 10-gallon aquarium while the feeding and breeding aren’t complicated. These fish were formerly known for their invasive nature that drove adverse ecological impacts in those areas.

Category Rating
Level of care Easy
Temperament Aggressive(male to male), Active
Appearance The Male appears with a swordtail.  Colors and motifs vary for different species.
Life expectancy 20 years
Size 14-16 cm
Diet Omnivore
Family Poeciliidae, Livebearers
Tank size 10-20 gallon
Tank environment It can survive in a hard, temperature-controlled water environment
Tank Mates Males should be separated. The ideal ratio: three females for one male.


Xiphophorus About

It has just gained some popularity among aquarium fish lovers. People may be more familiar with their popular name, the swordtail fish with various species to list. Each species is differentiated by its color, motifs, fin, and origins.

Just like its popular name, It has a unique sword-shaped tail that distinguishes it from other fish of the same size. For aquarium fish, the red Xiphophorus variatus seems to be more common than the others. The males have a long anal fin that can easily distinguish them from the females.

In general, male Fish is pretty aggressive towards other males. These fish have an invasive nature that has driven adverse impacts on the freshwater ecosystems in some regions.

While These fish are omnivorous, plants and greens are the fundamental parts of their diet.  They can eat insects, crustaceans, worms, and other living foods with no problem.

The male Xiphophorus can grow up to 14.0 cm while the female up to 16.0 cm. Distinguishing males and females by their size could be tricky. The males have a signature long fin that easily distinguishes them from the females.

Xiphophorus Types/Species

There are actually different species in different regions. However, some species have successfully gained popularity as an outstanding choice for aquariums including helleri, variatus,  and maculatus.

  • Helleri or the Green Swordtail fish is undoubtedly the most popular Xiphophorus species. This species is distinctive for its medium-large swordtail that became the “benchmark” of other swordtail and platyfish.
  • Also known as the variable platyfish, Xiphophorus variatus comes with eye-capturing color and the shape of the fin.
  • Xiphophorus maculatus or the Southern Platyfish that has a close tie to the Xiphophorus helleri or the green swordtail. Not only can you both be tank mates, but you can also interbreed the green swordtail and the Southern Platyfish and create exotics species in your tank.

Despite those popular fish, there are more Xiphophorus species you can find in the market. These fish are different from each other especially in the fin size, color, motif, and general shapes. However, Xiphophorus species share similar characteristics and requirements when they’re put in the aquarium.

Xiphophorus Tank Requirements & SetUp / Tank Guides

While Xiphophorus fish aren’t difficult to maintain in general, they need proper tank setup and requirements to survive and grow in the aquarium.

The water in the tank should be maintained in a pH range of 7.0 – 8.0 for an optimum Xiphophorus living environment. You must control the temperature between 22 °C – 28 °C so you may consider investing in a heater for your aquarium. The water hardness would be better maintained at  10-28 dGH which isn’t a difficult task for aquarium hobbyists.

You can use a 10-gallon aquarium for Xiphophorus fish but you may consider the larger tank if you want to keep them with larger fish or tank mates. Ideally, you can use a 20-gallon tank to provide these active fish more space to move around in the Aquarium.

Practically, you need a bigger aquarium if you have more types of platies and swordtails in one place. You can follow the basic rule of one gallon per inch to measure the ideal size of tank you’d use to keep Xiphophorus fish.

If you want to setup aquatic plants and bioloads in the aquarium, then it consequently increases the size of the tank.  Take a proportional measure of the landscape and groups of fish you want to keep in one tank.

Xiphophorus fish prefer low to no water current so you need to find the canister filter should have lower output. You can use internal filters, under gravel filters, and keep the setup to produce a very low water current.

A heater would be a great investment to keep your Xiphophorus fish comfortable. However, you’d need to invest in a thermometer or monitor the temperature with a thermostat to prevent overheating.

You must have proper lighting if you decide to install aquatic plants in your tanks. It would depend on whether the plants require low or high light but you can start with 4500-7000k. Keep your plantation proportional and ensure you provide Xiphophorus with more space to swim around.

Maintaining the plant could be tricky with more quantities set in your aquarium. You better use the durable substrate that already contains nutrients to maintain your plantation.  

CO2 setup must be a concern if you use a specialty or a bigger proportion of plants. Keep the best possible CO2 level to keep the plants alive but don’t disturb your platy and swordtail fish. If you don’t want to invest in a CO2 setup, you may consider the silk fake plants instead.

Xiphophorus Tank Mates

Xiphophorus fish are incredibly active and tough enough so they can get along well with other fish in a tank. Even bigger tank mates wouldn’t be a problem as long as it’s not big enough to eat your swordtail and platy fish.

Swordtail and platy males can become aggressive towards other males. At this point, you can either separate them into different tanks or maintain some hiding places in your aquarium if you want to keep them in one tank.

Some tankmate ideas for your swordtail and platy fish include

  • Guppies
  • Tetras
  • Mollies
  • Gouramis
  • Barbs
  • Characins
  • Corydoras

Platy fish and swordtail fish are great tank mates and they could possibly be interbred as well. If you want to experiment with other species, be sure they can get along with Xiphophorus fish.  The larger and the more tank mates you want to add, the larger tank you’d need.

Xiphophorus Diets/Food/Feeding

Xiphophorus fish are generally omnivores. While they can take live foods, dried frozen foods, and flakes, plants or greens are actually the important elements of their diet.

Dieting diversification is very important to keep the optimum health of your Xiphophorus fish. Despite those meaty foods, vegetable foods and thin algae would be great contributors to their diet. Culturing algae in the tank could be full of hassle, but you can use the processed foods with algae or green supplements.

For practical reasons, you can use vegetable-supplied flakes as the main element of the diet and you can boost the nutrients with live foods.  Always use high-quality flakes or pellet foods and for live foods, you can use insects, bloodworms, brine shrimp, and spirulina. Vegetables can include spinach, peas, squash, or cucumber.

Xiphophorus Breeding guideline

Breeding Xiphophorus isn’t difficult even when done in the 20-gallon tank. You wouldn’t have to specifically setup a  breeding tank and there are no specific actions required to breed these fish.

Xiphophorus that includes platies and swordtails are livebearing fish that refer to their ability to give birth free-swimming fries rather than laying eggs. A general tank setup previously mentioned above is already enough for any aquarist to induce breeding.


Since the male Xiphophorus could be very aggressive to other males when mating time, it’s very important to keep at least three females for one male. This way, you can prevent bloody battles among males. 

It’s also easy to notice whether your Xiphophorus fish are pregnant. The swelling abdomens are the obvious sign and when the skin has been stretched enough, you can possibly see the developing eggs inside the females. The gravid spot or the black mark on the abdomen is another sign of obvious pregnancy.

A female Xiphophorus can give birth to up to 80 fries for several broods per year. The pregnancy period is around 30 days before females give birth to the fry.

When breeding, you must lift up diets to cover the nutrient requirements of the pregnant Xiphophorus and the fry. Dry food, infusoria, and egg yolk, or specialty foods can be used to feed the fry.

Xiphophorus fish don’t necessarily need a breeding tank but they may eat their own fry in particular conditions.  It depends on your goal because a separate breeding tank means you’d have to deal with hundreds of Xiphophorus fry to feed on. Without a breeding tank, parental eating can be an effective population control if you want to keep one or two tanks in your room.

In general, no specific requirements for breeding Xiphophorus, only the proper and comfortable tank setup. Xiphophorus fish become fertile and ready for mating at the edge of six months.