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Goldfish is a freshwater fish that is very popular among aquarists, both amateurs and experienced. Goldfish has been bred in isolation for over a thousand years.

Due to cross breeding, there are several varieties of goldfish that vary in the body size, shape, coloration and fin configuration.

Pregnant Goldfish

Pregnant Goldfish

Some of the common colors that you may find in the market include white, brown, black, orange and yellow.

Breeding Requirements for Goldfish

Breeding goldfish in captivity can be a challenge for most aquarists. You need to get the goldfish conditions similar to those in the wild.

Some basic requirements include, plenty of space in the tank, the goldfish should be well fed with a balanced diet and the water should be in the ideal condition.

Goldfish Breeding Setup

Goldfish Breeding Setup

Goldfish Breeding Setup

Before beginning your goldfish breeding journey, you must first make sure your main tank is well set with a filtration system, plants, especially live plants such as hornwort, a heater and a spawning mop.

A spawning mop is not only recommended because it helps to protect the eggs from their parents, but also, it makes it easy to move the fry into a separate tank once they are hatched.

Apart from setting up the main tank. You also need to set up a different tank where the fry will be kept once they are hatched.

Temperature for Breeding Goldfish

In the wild, goldfish breed in the warm season, spring. Therefore, breeding for goldfish is triggered by a change in temperature, from the cold winter season to the warmer spring.

To replicate that in captivity, you need to adjust temperatures accordingly. First set the tank into cold temperatures of about 10 to 12 degrees Celsius.

Then when you want to trigger the goldfish into breeding, raise the temperature of the water from cold to ranges of about 20 to 23 degrees Celsius.

Goldfish Mating Behavior

Here is a great video of goldfish mating dance:

Differences Between Male and Female Goldfish

Differences Between Male and Female Goldfish

Differences Between Male and Female Goldfish

It is not very easy to tell the difference between a male and a female goldfish, because there are no necessarily visible external organs.

For you to tell the gender of the goldfish, you have to wait until they are sexually mature or during the breeding age.

Goldfish get to sexual maturity when they are about one-year-old. To tell if your goldfish is male or female, below are a few pointers:

– Shape of the Goldfish

Looking at the fish from above, female goldfish appear to be usually shorter and rounder in their abdomen area. When they get near the breeding season, they become very plump, swelling with eggs on either one side of the belly or both sides.

However, it is important to note that a swollen belly can also be a sign of bacterial infection. Male goldfish on the other hand appear thinner and longer in their abdomen compared to their female counterparts.

– Observe the Vent Shape of the Fish

The vent is located under the anal fin. It is the part that releases a goldfish’s waste. For female goldfish, their vent can be seen from the side.

When the female gets closer to the spawning season, their vent appears to be a small protrusion that is whitish in colour. Male goldfish, however, have a longer and indented vent compared to the females’.

– Check for Breeding Stars on Gills, Body and Fins

Breeding stars are also known as breeding tubercles. They are little white dots that look like grains of salt. They mostly appear on the front fins of the fish, the pectoral or on the scale.

If you see breeding stars on your goldfish, it means it is male. However, on very rare cases, they also appear on female goldfish and a male goldfish may fail to show the stars depending on the tank conditions.

– Examine the Shape and Length of the Front Fins

Male goldfish have front fins that are longer and thinner compared to the female goldfish whose front fins are shorter and thicker.

– Watch the Fish for Breeding Signs and Behavior

This is probably the most obvious sign to tell if a goldfish is male or female. Males are always seen chasing the female around the tank, pushing and nudging them.

Females on the other hand are always running and most times they have torn fins.

How do You Know if a Goldfish is Pregnant?

Although goldfish do not necessarily get pregnant, that is, carry and gestate a foetus, they do carry and develop eggs in their belly which they then lay for fertilization.

There are a few crucial signs that will tell if your goldfish is pregnant or not;

– Changes in Their Body Size and Shape

Female goldfish are generally rounder. However, when they get pregnant, they develop a large belly that is easily noticeable, especially when they get close to laying eggs.

– Changes in Activity Level

Female goldfish that are especially near to lay eggs appear sluggish and are mostly hiding behind plants or in shelters such as rocks.

– Changes in Feeding Behavior

Pregnant goldfish have a low appetite. They eat less food or refuse to eat at all, especially when are almost laying the eggs.

How Long Does it Take for Goldfish to Lay Eggs?

This is How Goldfish Eggs Look Link on a Plant

This is How Goldfish Eggs Look Link on a Plant

There is no definite time that the goldfish stays pregnant but they carry the eggs until they are fertilized by the male.

After release and fertilization, goldfish eggs hatch within two to seven days with the right water conditions and requirements.

How Often do Goldfish Breed?

Goldfish breed depending on the water temperatures. If the water temperature is regulated accordingly, they breed between 2 to 3 times a year or more, depending on where you live.

How Many Eggs do Goldfish Lay at Once?

Goldfish females lay up to 1000 eggs at once. However, not all the eggs are fertilized, therefore the number of fry will depend on the number of fertilized eggs by the male goldfish.

Unfertilized eggs are eaten up by the rest of the goldfish or they decompose in the tank.

Do Goldfish Eat Their Babies?

Goldfish make very horrible parents. They will eat the eggs and the newly hatched fry.

To keep them safe, it is important to get a spawning mop to keep the eggs safe, and prepare a separate tank for the fry where you will transfer them into as soon as they are hatched.

Wrapping Up

Breeding goldfish can be a challenge for aquarists. However, the trick is to wait until they get to maturity and adjust water temperatures from cold to warm to trigger them.

Goldfish do not make very good parents, therefore separate the fry as soon as they are hatched, or they will become a meal to the older goldfish. Enjoy breeding your goldfish!

Written by Fabian

Hey, I'm Fabian, chief editor at Aquarium Nexus. I really enjoy the aquarium hobby and love sharing my experience with others. If you have any questions feel free to contact me or leave a comment below.

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