If you have platyfish and want to know if one of them is pregnant, there are certain things you’ll need to look for. 

This is an important part of breeding any type of fish. When you know that your fish is pregnant, you’ll be able to prepare for their offspring.

What to Look For

There are a few different things that you should look for when trying to determine if one of your platy fish is pregnant. These fish are livebearers, which means the fish come out of the mother swimming freely. You won’t have to wait for any eggs to hatch.

1. Physical Changes

When a platy fish becomes pregnant, it will gradually take on a darker external coloration. If the fish already has dark scales, you probably won’t notice any change in their color. If your fish is going to give birth to white fry, you will see small black spots appear on their body.

As the eggs begin forming inside of the fish, their abdomen will swell and begin protruding. The pregnant platy fish will appear significantly bulkier than the rest of the fish in the tank.

2. Behavioral Changes

It is also fairly common for pregnant platyfish to behave differently in certain ways. For example, the expectant female might start pursing the male, following it around. They might also hide out in a part of the tank where no other fish go. The latter behavior often happens just before the fish gives birth to the fry.

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Tips for Caring for Your Pregnant Platy Fish

It is crucial that you take proper care of your platy fish while it is pregnant. These tips will help to ensure that it gives birth to healthy offspring.

1. Get a Breeding Tank

It is recommended that you get a separate tank that is just for the male and female, as well as the eventual fry. Make sure that the tank is large enough to accommodate all of these fish comfortably. A minimum 10 to 20 gallon tank will be required for this purpose.

2. Put in Some Plants

You should have a decent number of plants in the breeding aquarium. Java moss and duck weed are both two great choices for these fish. These plants will oxygenate the aquarium, and they can even promote breeding.

3. Carefully Monitor the Temperature

The temperature of the water in your pregnant fish’s tank should be set at 77 to 80 degrees Fahrenheit at all times. The lower the temperature goes, the longer this whole process will take.

4. Place the Tank in Direct Light

The tank should be in direct light to encourage reproduction. You should try to keep it by a window that receives bright sunlight in the afternoon. It will be necessary to invest in some good lights to illuminate the aquarium at night.

5. Take the Males Out

Once you have confirmed that your platyfish is pregnant, you’ll want to take any males out immediately. The males will probably chase the female fish, which can take a toll on their overall well being.

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When Your Fish Gives Birth

You can expect your platy fish to give birth during the night. The fish’s cloaca will appear dilated just before they are ready to give birth.

The offspring will come out of the mother one at a time, swimming around her for a while before settling down. You will most likely see the tail of the fry come out of the mother first. It can actually take up to six weeks for these fish to give birth to all of their offspring. The birthing process usually takes only a few hours, but it’s important that you are prepared just in case.

The Breeding Box

If you are expecting one of your platy fish to give birth, you’ll need to have a breeding box set up. This isolated area within the tank will keep the fry safe after they come out of the mother. Otherwise, there is a good chance that the offspring will get eaten by the adult fish.

Feeding the Fry

It’s also important that you know what to feed the fry once the female has given birth. These tiny little fish will eat just about any food that you put in the tank. Make sure that you choose a food that is loaded with protein. This will help them grow strong so they can get off to the best possible start, developmentally speaking.

Once the new fish are a few days old, you can start giving them micro worms, daphnia, and brine shrimp. While flake food is a good choice, you should also give them at least a little bit of the live variety as well. A well-balanced diet is crucial for keeping your fish healthy from the time they are born.

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How many fish will my platy give birth to?

Platy fish can give birth to as many as 40 fry over the course of hours or even weeks. Keep in mind that the temperature and softness of the water can have a big impact on this.

Is it normal for pregnant play fish to refuse food?

If your pregnant platy is not eating, it might be due to stress. You might want to try removing one or two of the other fish in the tank.

How do I know if my fish is just sick and not actually pregnant?

It is possible that your fish is sick instead of pregnant. Try adjusting the temperature and/or pH of the water in the tank and see if their bloating decreases.


  • Platy fish that are pregnant often become bloated with a noticeably distended abdomen.
  • You might also notice the expectant female taking on a darker coloration.
  • When a platyfish becomes pregnant, it sometimes chases the male around the tank.
  • Make sure that you set up a separate breeding tank for the fish you want to mate.
  • Put a breeding box within the tank to protect the fry so they don’t get eaten by any of the adults.
  • Closely monitor the temperature and pH of the water in the breeding tank throughout the female’s pregnancy.
  • It can take up to several weeks for a platyfish to birth all of its offspring, but this process usually only lasts a few hours.
  • You can feed the fry regular flakes to eat, but you should give them some live food as well.
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Hi! I'm Anna and I´m a certified cynologist (KAU, ACW). Expert, blue cross volunteer, owner of Chinese crested kennel "Salvador Dali" and breedless friend called Fenya. "I can't imagine my life without dogs and I totally support the idea #AdoptDontShop".