Sexing Goldfish: 6 Ways to Tell the Gender of Your Goldfish

 Celestial Eye Goldfish
Celestial Eye Goldfish


You don’t have to want to breed goldfish to be interested in your goldfish’s sexual orientation. Understanding the gender of your fish will help you better understand the behaviors they display. While a female pursuing a male around the tank and nibbling at him is probably bullying, a male chasing a female and nipping at her is probably breeding activity. Here are some things you need to know about sexing goldfish in order to better comprehend and care for your fish. Perhaps today is the day you learn that Patricia, the goldfish, is Patrick.

1 – Observe behavior

The very different breeding behavior of goldfish makes it simple to distinguish between males and females. In an effort to get a female goldfish to release eggs, male goldfish would chase her and nip at her rear end. You can witness several males pursuing a single female. When the female engages in this behavior, she may get hurt when trying to flee the males, although typically the males do not harm the female’s fins.

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2 – Examine the vent

The external excretory and reproductive organs that mammals have are not present in goldfish, which is one of the major ways in which goldfish anatomy varies from that of mammals. The bodily opening known as a vent, which is present in goldfish, is used to expel waste and genetic material, including sperm and eggs. Male goldfish often have a flat or inward-turned vent, whereas females typically have a slightly outward-turned vent.

3 -Breeding stars

Male goldfish will grow breeding stars when they are prepared to reproduce. Because they resemble salt crystals, these tiny white flecks are sometimes mistaken for ich. While ich covers the body randomly, breeding stars are concentrated on the gill plates and pectoral fins. When chasing and prodding the female at her vent to get her to release eggs, males employ these breeding stars.

4 – Body Type

Females will start to fill up their abdomens when they start to lay eggs when they are ready to spawn. A female goldfish that is slightly rounder and larger than usual is probably a pregnant woman because male goldfish do not alter in shape when they are ready to spawn.

5 – Fin Form

The pectoral, or front, fins of male and female goldfish are clearly different from one another. If you have goldfish that are very active, it may be challenging to identify these distinctions. Female goldfish often have thicker, shorter fins, while males typically have longer, narrower fins. When compared to fancy goldfish, single-tailed goldfish are simpler to distinguish from one another.

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You can easily tell the sexes of your goldfish if you watch them spawn. Large numbers of orange eggs will be released by female goldfish, and males will follow behind to fertilize the eggs. You might notice orange eggs in different places throughout your tank because females have been known to start releasing eggs while still trying to flee from the males.


It’s difficult to figure out your goldfish’s gender! Goldfish are active fish who always appear to be somewhere. It can be very challenging to get them to remain still long enough for you to take a close look at factors like vent and fin form. Although methods like observing for behavioral changes and spawning are much more effective, if you don’t want to risk having goldfish fry, you might want to try to identify the sex before spawning starts so you can separate your males and females.


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