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How to Tell If a Goldfish Is Pregnant

Goldfish are one of the most common pets people get, especially when they want a low-maintenance friend and companion to have in their home. While healthy goldfish are easy to care for, they are still living, breathing animals that get sick, have fights, and reproduce when it’s time. Goldfish pregnancy is not something you should worry about, but it can happen unexpectedly and you might get lots of baby fish all of a sudden. So, how to tell if a goldfish is pregnant? To make sure you are prepared for this, you can, take a look at the signs you will need to know about a goldfish pregnancy.

Pregnant Goldfish

Can Goldfish Get Pregnant?

Goldfish don’t get pregnant in a sense. They cannot carry their offspring inside of them and give birth. Instead, goldfish are oviparous creatures that carry eggs and lay them for fertilization and hatching. When they are preparing to lay eggs (to spawn), goldfish are considered to be pregnant. This process is referred to as goldfish pregnancy.

There are several ways to find out if your goldfish is preparing to spawn, which you can see if you carefully observe the behavior of both your male and female goldfish. However, the most important thing you’ll need to figure out is if the conditions are right for the spawning of your fish.

In order for a goldfish to get pregnant, the female will need to have the following:

  • Be at least one year old
  • Be bigger than four inches
  • Be in a breeding season (indoor goldfish may spawn at any time of the year.)
  • Have an appropriate water temperature for the spawning of your goldfish

Finding Out Your Goldfish’s Sex – Differences Between Male and Female Goldfish

With fish, it may be difficult to tell between goldfish males and females. However, just because they might seem similar, you need to be able to find out your goldfish’s sex. It’s always a good idea to check the gender of your goldfish to avoid having any surprises and having to deal with many fish babies.

Luckily, there are differences between male and female goldfish that you need to be aware of once you get them to your tank.

Females will have a rounder and thicker body shape that is deeper-bodied, especially than looking from the side. The females will have a fuller and rounder belly, even when they’re not pregnant

As the breeding season arrives, the female goldfish are going to develop eggs that can cause a bulge to appear on one of their sides and make them look asymmetrical or even lopsided.

The anal opening (also referred to as a vent) of a female goldfish is much rounder than the male goldfish, and it will protrude from the body slightly once the breeding season arrives. If they’re viewed from the side, the vent can be like it is a raised surface on the abdomen of a female.

Male goldfish have a thinner, longer, and more streamlined body shape with small white spots called tubercles, located on their gill shields or gill covers. They can also appear on the pectoral fins, as well as the face and the scales on the body of a male fish. The tubercles only appear and last during the breeding period, but older males that lived through several breeding seasons can have tubercles all year round.

However, even though the presence of tubercles is a good sign that your goldfish is male, the absence of tubercles does not mean that the fish is female since not all males will develop tubercles.

There is also a difference in the pectoral fin of the goldfish. While the female’s fin is rounded, the male’s is longer and more pointed, but also thicker and stiffer than the female’s.

Unfortunately, these are just subtle signs to identify the gender of your fish. It may take some time until you can spot them faster and get experienced in noticing these signs as soon as they happen. The best way to know the sex of your goldfish is to consult a vet.

You may also like to check out our article on how long do goldfish live.

Goldfish pregnant

Goldfish Mating Behavior

Before the mating starts, you will need to look at how your fish behave. The behavior of male goldfish can be a great indicator for the breeding process, even better than the behavior of pregnant goldfish.  Male goldfish that will spawn are often seen chasing and bothering the female goldfish, as an attempt to encourage them to lay the eggs. At times, they might also nudge the female’s bellies to tell them it’s time to lay their unfertilized eggs.

Another way to tell if the male goldfish is spawning is to look at their tubercles. Tubercles are small white bumps that develop in expectant male goldfish on their head, gills, and pectoral fins. They can be very hard to see, so make sure you don’t base your conclusions on trying to notice these tiny bumps.

To see if you have a pregnant goldfish, you will need to look out for any physical symptoms, like:

  • Changes in the size of the pregnant goldfish
  • Change in the shape of the pregnant goldfish
  • Changes in the activity levels of the pregnant goldfish
  • Changes in the feeding behavior of the pregnant goldfish

Since female goldfish are generally rounder, it might be difficult to figure out when they are carrying eggs. But, if they have a noticeably larger belly that sticks out, then it’s probably a sign that your pregnant goldfish will lay eggs.

When goldfish are preparing to lay eggs, they will usually slow down, be less active, and appear slightly sluggish. Pregnant goldfish will also eat less before they spawn. If your pregnant goldfish start refusing their food, it can indicate that they will lay their goldfish eggs soon.

Pregnant Goldfishes

Breeding Goldfish

If you want your fish to produce offspring and encourage them to mate, there is not much you can do in that area. All you have to do is make sure females and males are in the same tank during the breeding season. However, the breeding season for indoor fish can be during any time the water is not too cold, so make sure you carefully observe your fish and notice your pregnant goldfish.

But what can you do to make sure you get goldfish babies? You will need to care for the spawn. Goldfish are actually known for eating a goldfish egg and their fry. To properly take care of your spawn, you’ll need to follow these steps:

  • Make sure you have a specific spawning mat or create one from an unused mop head.
  • Remove the breeding ground and place it into a separate tank after spawning happens.
  • Monitor the color of the eggs. Fertilized eggs will be golden brown, while unfertilized are white.
  • Check the spawning mat you previously set after 12 hours and remove any unfertilized eggs.
  • Make sure the water temperature is 84 degrees or at least 70-75 degrees (it will take longer with a lower temperature).
  • Wait for the fertilized eggs to hatch (46- 54 hours for 84 degrees or 5-7 days for 70-75 degrees).
  • Monitor the fry. The fry will survive off their own yolk sacs while it is possible.
  • Once the yolk sacs are empty, you will need to feed them live food (daphnia and brine shrimp) approximately 3 times a day.


  1. How to Tell if a Goldfish Is Pregnant – wikiHow
  2. How to Tell If a Goldfish Is Pregnant – Cuteness


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1 Comment
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    Eat like a bear diet June 29, 2022 at 3:12 pm

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