Can Mollies and Platies Breed?

Despite sharing multiple traits, mollies and platies can’t breed with each other. They’re not compatible breeding mates because they don’t belong to the same family.

As an aquarist, you’ve probably heard of how to get different species to mate with the hope of producing more robust offspring. However, not all species are destined for breeding, such as mollies and platies.

They can, however, breed with other closely-related species. In this post, we’ll talk about why these two can’t breed, and which species make compatible breeding mates for each one.

Let’s dive in.

Can Mollies and Platies Breed?

No, mollies can’t breed with platies. As we mentioned above, each of these fish species belongs to a different family.

Mollies belong to the Poecilia family, whereas platies belong to the Xiphophorus family. As a result, each family contains a different genetic make-up that makes it impossible for them to breed.

Because of their different DNA, the eggs won’t be fertilized. However, if they do happen to mate, the resulting offspring is weak due to unstable genes. Subsequently, they won’t be able to survive long and almost always die prematurely.

Sailfin Molly

Which Species Can Mollies and Platies Breed With?

So, now we know that mollies and platies can’t breed with one another. Yet, can they mate with other fish species that belong to the same family? Definitely!

Compatible Breeding Partners for Platies

Platy fish are famous for mating mainly with swordtails. They’re both tropical freshwater fish that thrive in warm temperatures with plenty of room to swim around freely.

Remember to place three females for every one male to keep the mating ratio balanced. Plus, it helps avoid any aggressive behavior on the male’s part.

Then, wait about 28 to 30 days, and you’ll have an average of 50 fries per batch.

The interesting part is that platy fish are live bearers. This means that the eggs develop and hatch inside the pregnant female. Then, it gives birth to live babies that quickly catch on to their surroundings.

Compatible Breeding Partners for Mollies

On the other hand, mollies can easily breed with endlers and guppies. Similar to platies, you have to keep the female to male ratio at an even 3-to-1.

After mating, the female’s gestation period can last between four to five weeks. After that, you can expect to see close to 100 fries in each live birth.

Mollies are also live bearers. So, they give birth to live baby mollies instead of laying eggs and leaving them to hatch like other fish species.

If Mollies and Platies Can’t Breed, Can They Still Be Tank Mates?

Just because mollies and platies aren’t compatible species for breeding doesn’t mean they can’t enjoy each other’s company. As a matter of fact, they’re both known for their laid-back, easy-going demeanor, which makes them perfect tank mates.

The most important thing is to get an ideal-sized tank. A 30-gallon tank, or more, should be sufficient to ensure that both fish can swim freely and not get in each other’s way.

Mollies are larger than platies. So, that’s something to keep in mind when choosing the tank, decor, and filtration system.

Better still, they enjoy the same water parameters. For example, they both like their water at a pleasant 78°F degrees with pH levels between 7.0 and 8.5.

Also, when it comes to water hardness, both mollies and platies thrive in levels of 15 to 30 degrees of general hardness (dGH). This is basically the number of minerals, mainly calcium and magnesium, present in the tank water.

Both these minerals help manage the fish’s metabolic processes, boost ion exchange, and build up their bone structure. So, if the water’s hardness is higher or lower than the fish’s optimal range, it can affect their growth and overall health.

How Can You Tell the Difference Between Mollies and Platies?

One reason why aquarists tend to believe that mollies and platies can mate is that they’re similar in appearance and behavior. Nevertheless, to the experienced eye, there are several differences between these two species.

Take a look.


When it comes to their appearance, mollies are sleeker than platies and more prominent. The females can reach up to 4.5 inches, while the males are slightly shorter, growing only to nearly 3.5 inches.

Still, the males tend to be more aggressive than the more agreeable platies.

Their mouths tend to face upward, which helps them skim the oxygen-rich top layers of the water. Another interesting feature is their convex tails and pointed heads.

As for tank decorations, mollies prefer tall plants where they can hide and lay low for a while. They also like caves and crevices.

As for the substrate, they enjoy sand as opposed to gravel. It provides them with even more areas to dig around and explore.


Platies are characterized by their round, short body structure. They grow to a maximum of 3 inches, yet the male’s pointed caudal fin makes it appear longer than it really is.

Their anal fins are fan-shaped rather than the convex tails of the mollies.

Their mouths are forward-facing, which helps them scoop up as much food from the surface as they can.

They’re more robust and energetic than mollies. Plus, they’re better at handling a wide range of environments.

For their tanks, platies prefer a gravel layer for their substrate. Like mollies, they like plenty of plants to fill the tank, but not necessarily tall ones.

They just want a place where they can hide and stay safe. In short, plants are a necessity for both adult platies and their fry.

Wagtail Platy Fish

A Final Note

So, can mollies and platies breed? Sadly, no, they can’t.

Because each one belongs to a different family with different congenital traits, making it impossible for the eggs to become fertilized.

That said, there have been instances where they’ve attempted to breed, only to produce weak fry with unsuitable genes, which results in their premature death.

The best thing you can do is breed them with species from their own families. Or, simply let them enjoy watching them interact together and enjoy each other’s company.