How To Tell The Gender Of A Goldfish? (All You Need To Know)

As an aquarist, you must be curious to know about the gender of your goldfish while you add them to your home aquarium. So, how to tell the gender of a goldfish? Let us find out.

Male and female goldfish have different body types and are easily recognizable after maturity. Male goldfish are thinner, whereas female goldfish are broader in shape. Other factors like breeding tubercles in males and swollen vents in females help to determine the gender of a goldfish.

The below article will discuss the differentiation between the male and female goldfish.

Is my goldfish male or female?

Male and female goldfish have different body types and are easily recognizable after maturity. 

Male goldfish are thinner, whereas female goldfish are broader in shape. During the breeding season, like chasing, some behavior can also help you differentiate between the male and female goldfish. 

The male goldfish rub himself against the female to make her release the eggs. 

Therefore many other factors like breeding tubercles, length of fins, and vent shape can help to differentiate between male and female goldfish.

In the below article, we will discuss all the above factors in detail.

At what age it is best to determine the gender of your goldfish?

You can determine the gender of your goldfish once they reach their sexual maturity, which is above one year of age. However, your goldfish can sometimes reach to their maturity earlier or later.

It is not possible to determine the age of your goldfish as soon as they hatch because it takes time for the changes to happen in their body.

It will be easy to determine the gender of your goldfish during the breeding season as you can see some changes like the breeding tubercles developing in your male goldfish’s gills, fins, and body.

Goldfish usually breed when the cold water gets warmer during the spring season.

Your pond goldfish can spawn three to four times a season in warmer climates, whereas goldfish in captivity under adequate water conditions can spawn all year long.

Therefore, it will be advisable to maintain appropriate water temperature to ensure healthy spawning.

Also read: Can Goldfish Get Pregnant?

How can you differentiate between male and female goldfish?

Here are the ways to determine between male and female goldfish

  1. Check for the breeding tubercles
  2. Examine the vent shape of your goldfish.
  3. Body shape
  4. Look at the shape and length of the front fins.
  5. Examine the signs shown by your goldfish during the breeding season.
  6. Releasing eggs and milt

Check for the breeding tubercles.

You can determine the gender of your goldfish through the breeding tubercles that develop in the male goldfish’s body during the breeding season.

The male goldfish develop white dots commonly on their gills and pectoral fins, known as breeding stars. 

However, you can discover these white dots anywhere in your goldfish.

Breeding tubercles are commonly mistaken for white spot disease in your goldfish.

It will be advisable to verify whether the breeding season is happening before providing any treatment to your goldfish. 

Providing treatment without verifying can disrupt the spawning time and affect the health of your tank or pond.

Here are the ways to differentiate between breeding tubercles and ich.

Breeding TuberclesWhite Spot disease (Ich)
Breeding tubercles appear in small dots in a regular pattern.White spot disease varies in size and appears in an unorganized pattern in your goldfish’s body.
Breeding tubercles are commonly found on the pectoral fins and in the gills of your goldfish.White spot disease appears randomly all over your goldfish’s body.
Breeding tubercles are only seen in the body of a male goldfish.White spot disease can appear in both male and female goldfish.
The above table shows the differentiation between male and female goldfish.

However, there is no clear statement behind the use of breeding tubercles in your goldfish.

The male tubercles can also be a differentiator between the male and the female goldfish or indicate a healthy male; a male with more tubercles is more robust than those with fewer spots.

Examine the vent shape of your goldfish

The vent is a part of your goldfish body located underneath the anal fins that helps your goldfish eliminate the body’s waste.

The goldfish also use the vent to release their eggs or milt.

Your male goldfish have a flat vent, whereas the female goldfish have a swollen vent.

You can see the vent of your female goldfish from the side. It is a whitish protrusion that appears when your female goldfish is close to spawning season.

Your male goldfish have a flat vent that is not noticeable easily as it is a small slit hidden away under your male goldfish’s tails.

Body shape

You can also tell the gender of your goldfish by studying their body confirmation.

Your male goldfish have a thinner body shape, whereas the female goldfish have a rounder and a thicker body shape. 

As your female goldfish come close to their spawning season, they will appear very chubby, having a swollen belly looking like a dumpling. 

However, there can be many reasons for your goldfish getting broader than usual. Some of them are as follows:

  1. Overfeeding can make your female goldfish appear wider than usual.
  2. Infections like dropsy can cause your female goldfish to look chubbier than usual.
  3. Abdominal infections can make your goldfish look chubbier than usual.

Look at the shape and length of the front fins.

Your male goldfish have longer and thinner front fins, whereas your female goldfish have shorter front fins with thicker leading rays.

However, if you have a long-finned goldfish such as velitail, it will be a task to determine the gender of your goldfish as their fins are so enhanced genetically.

However, you can use this trick to determine the gender of your goldfish if you have a group of matured goldfish of the same breed.

Examine the signs shown by goldfish during the breeding season

Your goldfish shows some signs like chasing during the breeding season that can help you to determine the gender of your goldfish.

The female goldfish releases pheromones in the water, indicating that she is about to release her eggs.

The male goldfish chases the female goldfish to make her release their eggs.

However, sometimes chasing might also be a sign of aggression by the male goldfish.

So, the chasing behavior of your fish must be combined with other indications like breeding stars in the male goldfish’s body.

Also read: Can Goldfish Lay Eggs Without Male?

Releasing eggs and milt

The easiest way to determine the gender of your goldfish is to spot them releasing their eggs or milt.

The female goldfish releases the unfertilized eggs, and the male goldfish fertilizes them by releasing their milt upon the egg.

Therefore, you should never squeeze the eggs out of your female goldfish as it can lead to severe health issues in your fish.

Also read: What To Do If My Goldfish Is Stressed?

Conclusion:

  1. You can determine the gender of your goldfish once they reach their sexual maturity, which is above one year of age. 
  2. It is easy to determine the gender of your goldfish during the breeding season as you see changes like the breeding stars developing in your male goldfish’s body.
  3. You can differentiate between the male and female goldfish by checking for the breeding tubercles and looking at the front fins’ shape and length.
  4. Breeding tubercles are commonly mistaken for white spot disease in your goldfish.
  5. So, it will be advisable to verify whether the breeding season is happening before providing any treatment to your goldfish. 
  6. The easiest way to determine the gender of your goldfish is to spot them releasing their eggs or milt.

Reference: NCBI

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