When you have reared your goldfish for a long time, it's normal that the next time to think about is breeding. It's just the natural path to take once you had successfully kept your goldfish healthy and happy. If you are attempting to breed your goldfish in your very own aquarium, you are going to need some preparation and pour in your attention.

It is indeed easier to breed goldfish in the bigger outdoor ponds. The goldfish in a relatively natural habitat, with more plants, oxygen, and space to lay their eggs on.

How to breed goldfish? The following guide will go through the steps to provide the best conditions that encourage the goldfish to breed with success.

How to Breed Goldfish: Basic Information You Need to Know


Sex of Goldfish

Before you start, identify the sex of your goldfish. Select a pair of male and a female to get it on. To identify the sex, wait for the breeding season to arrive.

During this period, male goldfish will sport "breeding starts," or white little specks on the pectoral fins edges and the gill covers. In addition, their vents are longer and open wider for the season. The females will have a rounder abdomen, which expands as more eggs are produced. A white protrusion of the vent can be spotted when they're ready for spawning.

The goldfishes shouldn't be too old or too young either since you would want the most eggs out of your chosen pair. Ideal breeding age ranges between 1-3 years, or when their head to body length is at least 3 inches. For the best spawns, make sure the pair is at its peak health, that is hearty appetite, good color, and perky behavior, and of course, with minimal genetic defects.


Breeding Conditions

The three main pre-requisite for the goldfish to breed are the following:

  • A water temperature of around 68°F

  • Lengthening days in spring

  • Water condition changes

The hormones of the goldfish are affected by the longer daylight hours. The hormonal changes kick start the mild production of the eggs for the spawning process. The spawning itself will be triggered by the water conditions and weather, or even delayed by them.



Spring is the ideal breeding time for goldfishes. An early breeding allows more time for it goes grow through the year as much as possible. Never start it too soon to avoid the risk of severe cold snap.

Early breeding limits the available feeds for the fry (e.g. mosquito wrigglers).

Spawning behavior changes with the weather condition. A hot environment, followed by rain to cool it down, often signals an ideal condition for spawning by next morning. For cold weather, the cooling of water temperature encourages spawning.

You can induce spawning easily just by placing your pair in the new environment, regardless of the temperature.

How to Breed Goldfish: a Step-by-step Guide


Pick Your Breeders

The robust young ones are always better for breeding due to higher sex-drive and high fertility (older doesn't mean more experienced). The ideal female mate should include large pectoral areas and rear. For the males, large (4 to 6 inches), fast swimmers are recommended. Another great sign for males is plenty of small tubercles sported behind the gills area.

To increase the change and variety of breeders, isolate your two best females and three of your best males.


Natural Spawning

Introduced your five chosen candidates into one aquarium tank and search for natural spawning. The male will show off a lighter tint right in the stomach area and swimming swiftly all over the tank, usually chasing the potential mates. The females will then lay their eggs in the safety of the shade of available plants. The males will follow up by distributing their sperm over the eggs. Fertilization will occur and you will most likely miss it altogether. If you did miss the procreation moment, look out for eggs around the plant life, those eggs are likely to be fertilized.


Artificial Insemination

This method will require only two goldfish of each sex. Gather them in one shallow tank. Gently grab your male goldfish and rub the vent area. This will release the sperm. Swirl the sperm around then do the same with the female. The eggs will be released and repeat the swirling once again. The sperm should combine with the eggs to fertilize.

Do be ginger with this method. Artificial insemination could bruise your goldfish easily, so practice caution and maintain light pressure with the clearing.


Goldfish Eggs

Goldfish will gobble up their own eggs because they are born to be in that way, so don't leave those adults in the same tank as the eggs! Once you spot the eggs is there, remove the eggs from the location as soon as possible

To remove the egg, carry over the whole plant or spawning mop if available, and place them in a smaller tank specially set up for the fry.

The temperature should be at similar temperature as your main tank, ideally between 68°F to 74°F. Adjust the temperature using a heater as necessary.

Do your due diligence to get rid of darker color eggs. Lighter ones are more likely to hatch, although leaving the darker eggs around would not affect the health of the whole tank.


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