What to Know About Platies

Medically Reviewed by Vanesa Farmer, DVM on January 05, 2023
5 min read

If you’re looking for simple, colorful additions to your freshwater aquarium then you need look no further than the platyfish. Platies are small fish that come in a rainbow of hues and easily adapt to life in tank environments. 

On top of being excellent pets, these fish are also popular scientific research subjects. Studying these fish has lead to important contributions in the fields of ecology, evolution, and genetics. So — if you choose to bring these fish home — know that you’re becoming a new member of an engaged community of platy enthusiasts and researchers.

Platies are in the order of ray-finned fishes. This means that they have stiffly rayed fins coming protruding from their bodies. In some cases, these rays take on distinct, exaggerated appearances. But this isn’t the case for platies. 

In fact, the scientific name for their genus is Xiphophorus which comes from the Greek words for “sword” and “to carry”. Fish within this genus either have long, elongated tail fins that resemble swords or they have regular, rounded tailfins. 

All of the species of fish in this genus with extended tails are referred to as swordtail fish. All of the species that lack these extreme tails are called platyfish. Two common species of platyfish are Xiphophorus maculatus — the southern platyfish — and X. varietus — the variable platy. Another popular platy is called the Mickey Mouse platy. It’s named after the distinct markings near its tail — which resemble the ears and nose of a popular animated character. 

Another common name for platies is moon fish.

The typical platy size is quite small — which makes them suitable for a lot of different aquarium set-ups. They grow to about 6 centimeters long but can be as small as a single centimeter in length — particularly when they’re still immature. The females tend to be slightly larger than the males. 

Both sexes have stout bodies and upturned mouths. 

The backs of these fish have eight to 10 soft rays. Both these rays and their tailfins have rounded shapes and — unlike their close relatives — never take on long, sword-like points. 

Natural platies have yellow and olive-brown coloration with two to five distinct black bars running up and down their bodies. But in aquarium settings, people have bred these fish to have a wide range of colors and hues. 

Examples of aquarium platy colors include: 

  • Silver with black highlights
  • Red with black spots
  • Golden yellow with orange highlights

Many species of fish lay eggs. But female platies give birth to live young. The brood sizes range from 20 to 80 individuals per batch. The young reach sexual maturity after three to four months and start reproducing on their own.

The fish breed very easily, so they’ll likely start having young in any setting where you’ve gathered males and females together — even in modestly sized aquarium set-ups.   

The exact platy lifespan depends on a number of factors like the exact species and the quality of their living environment. In general, the better you care for your pet, the longer it’ll survive. They typically live for about two to three years in captivity.

Most platy species are native to Central America. But the aquarium trade and human activity have spread them out to countries around the world. Today you can find them occupying waterways in: 

  • The U.S. — including the state of Hawaii and the territory of Puerto Rico
  • Jamaica
  • The Bahamas
  • Columbia
  • Madagascar
  • Sri Lanka
  • Australia

They can live in a number of different freshwater environments and can even tolerate higher levels of salt contamination than other species of fish. Examples of their preferred environments include: 

  • Warm springs
  • Canals
  • Ditches
  • Creeks
  • Swamps

Overall they prefer relatively slow-moving water with plenty of silt and plants for shelter and protection.

Due to their popularity in the aquarium trade, people throughout the world have ended up releasing platies into non-native waterways. Unfortunately, platies can become pests when they’re released into their non-native environments. 

They can out-compete many native species for food and other limited resources. Plus, these fish have much greater reproductive success and higher survival rates in waterways that are too degraded for native fish to thrive. 

In Australia, platies have become such a problem that the government has instructed residents to kill any platies that they catch in the wild instead of releasing them back into the water. They also encourage all fish owners to give their pets away to friends or bring them back to a pet store instead of releasing them into the wild. 

In fact — in countries like Australia — it’s illegal to release these fish in the wild because they’re considered a biosecurity hazard.

Platies are omnivores. They can survive off of much of the plant and animal life that they find in their environments. This includes: 

  • Worms
  • Crustaceans
  • Insects
  • Plant matter

In an aquarium set-up, you can try feeding them commercial fish pellets or flakes. Consult your local pet store for brand recommendations.

You can keep these fish in an aquarium all by themselves or mixed in with other species of fishes. Just make sure that you have a good balance of male and female platies. If you have too many males, they have a tendency to fight one another. 

They can adapt to a wide array of aquarium settings, but they do best in conditions that mimic their native environment. For platy’s this includes: 

  • A water pH of 7 to 8
  • A water dH — which measures water hardness — of 9 to 19
  • An ideal platy temperature range of approximately 65 degrees Fahrenheit to 77 degrees Fahrenheit 
  • Plenty of light — one study found that they grow and mature the best when given 18 hours of light and six hours of darkness each day 
  • Plenty of plant life — either real or fake — for them to hide in

Also, make sure that your aquarium has a tight-fitting lid. Platies can jump right out of the tank if they’re feeling determined enough.

Like all pets, your platies can develop significant health issues throughout their lives. Common problems in aquaculture communities include infections from viruses and parasites. 

Two common examples of diseases that affect platies are dwarf gourami iridovirus — which causes spleen and kidney problems — and gill fluke — which is caused by a parasite that uses snails as a host. They also get a number of common fish diseases like ich, fin rot, and velvet. 

Many fish diseases are fatal and it’s difficult to find a veterinarian that specializes in aquarium pets. Although fish medicine is a growing field, the majority of vets are trained to work in large-scale aquaculture settings and not with individuals. 

You can always try consulting employees at your local pet stores for advice on a health issue in your pet. Unfortunately, there’s no guarantee that you’ll find an expert on your particular problem. 

Overall, platies tend to be a healthy, sustainable breed that does well in most freshwater aquariums. Just make sure that you’ve got the right equipment and care information before you bring these fish home.