7 Ways To Tell If A Goldfish Is Male Or Female (With Pics)

If you want to know whether your goldfish is male or female, then you’ve found the right article! IN this article, not only will you find out the difference between both genders of goldfish, you’ll also learn the best times to tell the genders and much more!

So keep reading to find out everything you need to know!

How Can I Tell If My Goldfish Is Male Or Female?

There are several ways to tell the sex of your goldfish through their physical characteristics. We’ve listed these characteristics below to help you determine if you have Sally versus a Harry.

Observe the Goldfish’s Body Shape

One of the most obvious differences between male and female goldfish is their body shape. Males are generally slimmer and more streamlined, while females are rounder and more full-bodied. This difference becomes more apparent as the fish mature, and females will become noticeably plumper as they reach breeding age.

Look at the Pectoral Fins

The pectoral fins, which are located just behind the gills, can also provide a clue about a goldfish’s gender. Males will have longer and more pointed pectoral fins, while females will have shorter and rounder ones. The difference in the shape of the pectoral fins is more apparent in mature goldfish.

Examine the Vent Area

Another way to determine the gender of a goldfish is to examine the vent area. The vent is the opening located near the base of the tail, which is used for excretion and reproduction. In males, the vent is slightly concave, while in females, it is more rounded and protrudes slightly.

Watch for Breeding Behavior

During the breeding season, which typically occurs in the spring, goldfish will exhibit distinctive mating behaviors. Males will chase females around the tank, nipping at their fins and sides to encourage them to release their eggs. Females will become noticeably swollen with eggs and may display a more subdued coloration.

Observe Their Colors

Mature males often develop brighter coloration than females do and may also display tubercles or small bumps on their head and gills when spawning (this can vary depending on species). Females are typically duller in color than males but generally have fuller bellies due to egg development during spawning season.

Consult an Expert

If you are still unsure about your goldfish’s gender, you may want to consult with an expert. Local fish stores or aquariums may have staff members who are knowledgeable about goldfish and can help you determine the gender of your fish.

Breeding Tubercles

When males are ready to start making babies of their own, they develop breeding tubercles or breeding stars that resemble white pimples on their pectoral fins and gill coverings. These tubercles are usually rough to the touch, and it is speculated that they may be used during courtship or to fight off other competing males.

Females do not develop these breeding stars, so it is most likely a male if your fish displays these pimple-like spots. However, be careful not to confuse them with ich or white spot disease, which can infect either gender and usually displays a random pattern all over the body.

Male Goldfish & Female Goldfish Picures

To make it easier, here is a male goldfish vs a female goldfish.



How Old Does My Goldfish Need To Be Tell If They Are Male Or Female?

Goldfish need to be sexually mature in order to determine if they are male or female. Most goldfish reach sexual maturity around one year of age, although some can peak earlier at around nine months old.

Most of the physical and behavioral characteristics used to determine the sex of a goldfish will not be developed before the age of one, so it can be virtually impossible to determine your goldfish’s gender before then. The best time to determine whether your goldfish is a male or a female will occur during the first breeding season after your goldfish has reached sexual maturity.

Other Characteristics Of Male vs Female Goldfish

There are a few more characteristic differences you may notice between male and female goldfish as well.


One of the most obvious behavioral methods of determining your goldfish’s sex is observing what is released when spawning. Females will drop a lot of orange-colored eggs as they swim through the tanks, while males will milt what looks like cloudy white sperm.


Male goldfish tend to be aggressive when it comes to breeding season, while females prefer to be left alone. If your goldfish is picking a fight with another fish or insistently nagging, it is probably a male. Females will not engage in fighting behavior and rather tend to hide if overly bothered.

Raggedy Appearance

While not the best indication of sex determination, if you notice that your goldfish’s fins are becoming tattered and torn during the breeding season, it is most likely a female. Males can tend to be aggressive in their pursuit of females. As such, males will nip at females’ fins or push them into plants causing the female’s fin to rip and tear.

Males usually do not look as raggedy because fin nipping is not typical in male-to-male combat when they display aggression towards each other.

Just make sure your goldfish is not suffering from fin rot.

Goldfish, aquarium, a fish on the background of aquatic plants

How To Tell the Difference Between Tubercles and Ich?

Tubercles are a normal physiological response in male fish during the breeding season, while Ich is a parasitic disease that affects fish and can be harmful. The two conditions can be easily distinguished by their appearance and symptoms.  Here’s how you can tell the difference between these two tubercles and Ich.

Understanding Tubercles

Tubercles are small, white, pimple-like growths that appear on the head and fins of male fish during breeding season. These are a normal physiological responses in male fish as they prepare for reproduction. Female fish can also develop tubercles, but it is less common. Tubercles are typically harmless and will disappear after breeding season.

To identify tubercles, look for the following characteristics:

  • Small, white, pimple-like growths
  • Appear on the head and fins of male fish
  • Normal physiological response in male fish during breeding season
  • Can also develop in female fish, but less common

Recognizing Ich

Ich is a parasitic disease that affects all fish. It is caused by a protozoan parasite called Ichthyophthirius multifiliis, commonly known as “white spot disease”. Ich can be a serious condition that requires prompt treatment to avoid further complications.

The following are the symptoms of Ich in fish:

  • White spots or small white dots on their skin and fins
  • Spots can quickly spread and cover the entire body of the fish
  • Lethargy
  • Loss of appetite
  • Rubbing against objects in the aquarium

Find out why your goldfish might have white spots that aren’t ich.

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Here are some more frequently asked questions people have about the gender characteristics of goldfish.

When Do Goldfish Start Breeding?

Goldfish typically start to breed in the late spring or early summer months when water temperatures are at their peak (around 70 degrees Fahrenheit). Breeding usually takes place in shallow, plant-filled ponds as goldfish prefer these areas for mating.

Generally, male and female fish will produce several batches of eggs throughout the season which can be hatched with careful monitoring.

Can Goldfish Change Gender?

No, once a goldfish is born, it cannot change its gender. However, it is possible for some male goldfish to take on characteristics of female fish if their environment does not contain enough males. This phenomenon is known as “intersexuality” and occurs because the hormonal levels required for masculine traits have dropped significantly due to stress or a lack of water quality.


Goldfish are wonderful pets whose fun and animated antics can light up a room. Before you get down to the tricky task of choosing a name for your new aquatic amigo, there are a few things you need to know in order to determine whether you’ve got a male or female goldfish.

First, they need to be old enough to determine sex – at least twelve months old. The best time to determine sex is going to be during their first breeding season after they reach sexual maturity at the age of one.

There are several physical characteristics to help you figure out if you have a male or female goldfish, including the presence of breeding tubercles, pectoral fin and body shape and length, anal vent opening, and ventral ridge. In addition, behaviors such as chasing, fighting, and nipping can aid in sex determination.

Whatever the gender of your goldfish, take heart that once you’ve settled on the perfect male or female name that you won’t have to change because your goldfish is a he or she for life.