How Long Are Platy Fish Pregnant For? Here Is What You Need to Know
How Long Are Platy Fish Pregnant For? Here Is What You Need to Know

Platies are known to be small, tropical, live-bearing fish mainly found in Central America. Easy to care for and low maintenance, these are the ideal fish to have in your aquarium. Their breeding patterns are also pretty straightforward. So simple that if you put a female and male platy together in an aquarium, the chances are they will mate.  

If you are someone looking to breed platy fish, we have got you covered. But first thing’s first, you have to familiarize yourself with how long are platy pregnant for, how platies breed, whether they are pregnant or not, and how to take care of their offspring. We have put together a basic guide for you that will take you through the process of platy breeding leading to platy fish fry.

Get to Know Your Platies

Platies are popular in pet shops because they have a peaceful temperament and are very active in nature. One thing you are bound to notice is that these little fish are prolific breeders. Meaning they can regularly and readily reproduce in any community tank.

How Long Are Platy Fish Pregnant For? Here Is What You Need to Know
How Long Are Platy Fish Pregnant For? Here Is What You Need to Know

Platies are a part of the Piecilliidae family, specifically the Xiphophorus genus found in freshwater fish. These fish have characteristic features like ray-type fins and small size (usually about 2 inches). They are also commonly called variatus or southern platy fish. There are several hundred variations of these fish. Although the hybrid variations are more compared to specific breeds. This is mainly because of their increased demand as well as increased breeding between the aquarium-bred and wild-bred species. 

Platy Biology: How Long are Platy Fish Pregnant For?

Platies are considered adult fish as soon as six months of age but they can start breeding even sooner which is around four months or so. The reason we call them livebearer fish is because the pregnant platy gives birth to fry that is free-swimming. So, how long are platy fish pregnant for? It’s usually 24-35 days with most gestations occurring at 28 days. 

Most of the time, female platies are already pregnant when you buy them because they are kept with male platy fish in aquatic suppliers and stores. But if they are not, then you can just pair them with a male platy in a community tank leading to a potential birth every 4 weeks.  

Differences between Female and Male Platy

Now comes the curious question. How do we tall male and female platies apart? Well both of them have features that make one different from the other. There are hints of sexual dimorphism between the two within this species. Males have a pointy anal fin which is called a gonopodium. Its function is to inseminate the female platy. While on the other hand, the female has a fan-shaped wider anal fin and their sizes are larger compared to their counterparts. 

How Can I Tell If My Platy is Pregnant? 

Physical Changes

The physical changes confirm the pregnancy, but they take a couple of weeks after copulation to arrive. The first thing you need to do is to prevent adult fish from eating the baby platies. You can do this by identifying the signs of pregnancy and setting up the aquarium so that you are ready when the female platy gives birth. 

Depending on how long the platy is pregnant for, the female platy’s abdomen will increase in size and she will swim around with a dark spot on her belly, which is the most common determinant of pregnancy.

Behavioral Changes

Behavioral changes are some of the first signs to appear, so keep your eyes out for them. The female platy usually likes to shadow her mate around the aquarium when she is pregnant. You will find that as she nears around to giving birth, this pattern will reverse, with the male platy chasing her excessively. 

What Should I feed My Pregnant Platy? 

As we said earlier, platies are not high-maintenance fish. They will not need any special food. But it is important to remember that a pregnant platy will need an increased amount of food. She may also come off as aggressive when feeding. So remember to feed her well. 

How do I know if My Platy is about to Give Birth?

In order to stop platy adults from making baby platies their food, certain precautions can be taken before the female platy gives birth. Now you must be wondering how you can tell if she is getting ready to give birth. As discussed above, physical and behavioral changes can be a hint on what is going on with your platy. But at the same time, if you know when reproduction has occurred, you can easily tell how long the platy has been pregnant for thereby calculating the amount of time that has passed. 

Here are some of the things you can prepare:

Get your Breeding tank ready 

Depending on how long your platy has been pregnant, you are going to need a tank for that duration. Even though adult platies are pretty small and do not need a separate tank, it is important to remember that the fry are going to be born live and so may need a separate tank with substantial space to grow. For this purpose, a 10-20 gallon (40-80 liters) fish tank should act perfectly as a breeding tank. You can also add live plants like java moss, hornwort, and duckweed. 


A 10 to 20 gallon (40 to 80 liters) tank is sufficient for a breeding tank. Plants not only give the female fish a safe and secure place to give birth but also act as hiding spots for the newly born fry. And it is always a plus to have oxygen in the water. Moving onto water parameters, this is where it gets a bit tricky. In the wild, platies are found in still, warm waters with heavy vegetation and silt beds. In order to mimic this environment, temperature control is important in your breeding tank. 

Water Temperature

Water temperature kept between 70-75 degrees Fahrenheit (20-25 degrees C) is the optimum temperature needed. The pH of the water should be around 6.8-8.0 and the hardness of the water should be around 10-28 dGh. You should change at least 25% of the water every 2 weeks to maintain cleanliness. 

By installing a heater, you can keep the temperature at a constant rate in an acceptable range. If you do not have a lot of plants in your tank, you can add air stones to maintain the oxygen levels in the water. To make sure the nitrite and ammonia levels in the water are acceptable, you can invest in a testing kit to test the water regularly. One way you can protect the fish fry is to place the mother inside a breeding box. This box has little holes in it through which the newly born fry can pass through. You can also use a mesh net breeder to easily separate the fry from their mother. However, please be aware that in a lot of cases, such boxes may stress the fish, so consider this carefully.


You have to keep a lookout for signs of upcoming birth when it comes to your pregnant platy. It usually occurs at night. The fry are born tail first, one at a time. Although the normal batch can consist of 8-20 fry, a pregnant female platy can give birth to as many as 35 fry.  While the entire process lasts for a couple of hours, do not be taken aback if it lasts for longer than that. It is also possible that the female platy can give birth to more fry over the coming few days to weeks.

Once everything is done, you can remove the mother from the breeding tank. One fact to keep in mind is that adult platies do not have parental instincts and can eat the fry if given the chance. 

Baby Platy Feeding and Care

Newly born fry are tiny making them difficult to see. They are almost clear in color and are 7-8mm in length. They grow within 2-4 months and their color changes in the meantime as well. You can feed the babies crushed commercial flakes or liquid fry food. You can easily find food that is specifically made for live-bearing fish. 

After that, you give them micro worms, daphnia, or baby brine shrimp. They also enjoy blanched veggies like broccoli or zucchini. Be careful to remove any uneaten food so that the water stays fresh. The rule of thumb is to keep the fry separated from the adult fish until they are at least 2 weeks so that they do not get eaten. 


With their frequency and ease of breeding, platies are an excellent choice for you if you are a beginner looking to breed fish. Not only are the fry hardy but they are also easy to take of. You require very little equipment apart from a breeding tank (optional) to make sure there is a successful birth, thereby increasing the survival of the offspring.

And to answer the question about long platy fish are pregnant for, as a rule of thumb, around 28 days.