How to tell if my pufferfish is pregnant?

I have two pufferfish that swim actively in the tank. But lately I observed one of them behaving strangely. I became anxious and observed it all the time. Apparently, the water condition was perfect and there was enough food in the tank. But still, it would seem unhappy. I was about to consult a vet but then my friend told me that maybe I was about to have little pufferfish as my fish seemed pregnant! If you own pufferfish and you wonder when you’ll have that tiny fry then look for some signs in your female pufferfish.

Here are some signs that would tell you whether your pufferfish is pregnant or not:

If you are wondering whether your pufferfish is going to have babies then let me tell you; pufferfish don’t get pregnant. The female pufferfish produces eggs that are extracted and fertilized by the male pufferfish. Some signs that you’ll observe in female pufferfish while she is ovulating is that she might get settled in the bottom of the tank and remain there for days. Also, the belly would be swollen and pufferfish won’t eat anything. Although these are not very obvious symptoms, still they will help you understand your fish better.

Let’s understand how and when your pufferfish start producing eggs and what to do to favor fertilization.

Signs your pufferfish is pregnant

You’ll notice a few changes in your female puffer fish’s body and habits once it starts producing eggs. But these signs are not very prominent and obvious.

Another confusing thing about pufferfish is that you can’t Differentiate between male and female pufferfish. So, if you are looking for some signs that show your pufferfish is producing eggs then also make sure that the one you’re watching is a female!

Here are some of the signs that you might observe once your female pufferfish starts ovulating:

Not willing to have food

If you observe one of your pufferfish not willing to have food at all then it’s possible that she’s producing eggs. It might also be sick. So, you have to look for other symptoms too.

Pufferfish doesn’t like to eat anything when it’s producing eggs. You don’t have to worry but continue taking care of or by providing a clean environment.

Seem inactive

You’ll notice that your otherwise active pufferfish is now nowhere in the tank. It likes to settle in one place, usually behind the plants or rocks.

Not only female but male pufferfish also becomes inactive for spawning purposes. It selects a spawning site and takes care of the area by staying there all the time.

Likes to stay at the bottom of the tank

Pufferfish need a flat and hard surface to lay eggs on. So, she’ll prefer to stay at the bottom of the tank.

Make sure you provide a flat and hard substrate rather than the sandy ones.

Bigger belly

You’ll observe that your pufferfish have now become bigger in size. This is because it has started producing eggs so the belly has enlarged.

The ovipositor (egg-producing organ) becomes big and very prominent. So you might see a white spot on the belly as well.

How to ease the fertilization process?

Dwarf Pufferfish courtship and spawning behavior

Fertilization isn’t easy in the case of pufferfish. They are aggressive in nature and they will not settle down unless they want to.

Secondly, you never know who’s male and who’s female among your pufferfish. This problem leads to even fewer chances of fertilization.

Once you think a female pufferfish in your tank is just going to produce eggs, you can make the fertilization process easy by:

  • Adding at least five pufferfish in your tank. This would ensure that there are both male and female pufferfish in there. If you have just two pufferfish, both of them could be male or female.
  • Once the eggs are laid, the male pufferfish will fan them and protect them. He’ll also separate any eggs that have fungus on them. So, provide nutritious food to the male pufferfish so that he can take care of developing eggs. Provide live food that is rich in protein.
  • Make sure the substrate is flat and hard as pufferfish prefer flat and hard surfaces for mating. Sandy substrate isn’t favorable for them.
  • Once the male starts to protect the eggs, it’s better to remove the female pufferfish from the tank. The male can get aggressive if anyone tries to distract him.

The Bottom line

If you are curious whether your pufferfish is pregnant or not then look for some signs. If your pufferfish is about to lay eggs then she would like to settle at one place with minimum activity. Also, she might not be able to eat much food and the belly would seem large. You have to take good care of both female and male pufferfish to ensure fertilization.

Fertilization is not easy in pufferfish as you can’t differentiate between a male and a female fish. Yet, you can give it a try by adding almost five pufferfish in your tank. This can increase the chance of fertilization. Good luck with that!

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Nadine Oraby

My name is Nadine; I am a passionate writer and a pet lover. People usually call me by the nickname “Joy” because they think that I am a positive and joyful person who is a child at heart. My love for animals triggered me to create this blog. Articles are written by vets, pet experts, and me. Thanks for visiting. Your friend, Nadine!

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