The Aquarium Guide

Goldfish Series – Breeding Goldfish

In this next post of my Goldfish Series, I’m going to share a little about breeding goldfish.

By now, if you have been following the series, you should know the various types of goldfish and the proper way to feed your goldfish.

If not, here are the previous post of the Goldfish series:

Okay so let’s get back to today’s post.

Goldfish Series - Breeding Goldfish

Important facts when breeding goldfish

You need 1 year old goldfish

First, goldfish only become sexually mature at about one year of age and pet stores usually sell very young fish.

Try to purchase your fish about one year in advance if you plan to breed them.

Patience is very important, as compatible mates may be hard to find, or sexing the fish may be difficult, so you may find you have only males or females in your tank, which obviously, are not able to breed by themselves.

Breeding goldfish is not easy

Next, you need to understand that breeding goldfish is a time-consuming task that is pretty tricky to do in captivity.

It may take a while before they are ready to spawn and specific conditions must be met to provide proper breeding grounds.

Extra tanks are required

Also, you must provide extra space for the fry, as newly hatched fish cannot be kept together with their parents, so they need a separate tank.

Setting up the breeding tank

Choose a tank that holds at least 20-gallons of water and try to recreate the natural habitat of the goldfish with many bushy plants, either live or artificial.

Live plants have the advantage of acting like natural filters, so you will be able to use a weaker filter.

Aquarium plants are a necessary prop for a female goldfish to lay her eggs on.

You can also use a spawning mop, made of nylon fibers, but plants look more natural.

Improve your fish’s diet

A few weeks before planning to breed them, you should start introducing new, high-quality food in their diet: black worms or brine shrimp work very well.

It’s best to feed them several times a day in small increments, not more than they can consume in 2-3 minutes.

Leftover food spoils the water and makes breeding harder.

Introducing these tasty foods helps simulate spring, which is their natural breeding season.

During spring, new and fresh food is always available in all ecosystems, so this can be a great starting point in recreating ideal breeding conditions.

Simulate the breeding season

The most relevant seasonal changes are the temperature rising and the lengthening of days, so this is what you must do to let them know it’s time to spawn.

Gently lower the tank temperature to between 50-54° Fahrenheit, then after a few days, begin to increase it by 3 degrees per day, until reaching between 68-74° Fahrenheit.

Additionally, gradually increase the amount of daylight the tank usually gets at the same time with the temperature rise.

Fresh water will make them feel like spring is coming, so you will need to do partial water change every day.

Remove between 10-20% of the water and replace it with fresh tap water that has been previously conditioned.

Changing more than 20% of the water will stress your goldfish, so keep it in this range.

Breeding behavior

You know your fish are ready to spawn when the male displays white “pimples” on its fins and gills, and the female becomes a little rounder because she already produced the eggs she will lay.

A common breeding behavior is the male chasing the female and occasionally poking her in the abdomen.

This can easily be mistaken by fighting, but if you are certain you have sexed the goldfish correctly and they are indeed male and female, you won’t need to worry.

When the female becomes tired, she will search for a planted area and start laying her eggs.

She will, eventually, lay her eggs anywhere in the tank, and they will stick to whatever they fall on.

After the eggs are laid, the male will spray his milt over them to fertilize them.

Caring for the fry

You will need to remove the plant or spawning mop containing the fertilized eggs after a few hours, or the parents will eat them.

You must have the fry tank ready at any time, with water at the same temperature as the breeding tank and no deeper than 6 inches or the fry may be crushed by the weight of the water.

Also, only use a gentle, sponge filter to avoid the fry being dragged inside.

Another and safer option would be removing the parents immediately after spawning to avoid the eggs being eaten.

Parents are hardier than newly laid eggs and the fry should hatch in the same water they have been laid into, so removing the parents would be safer.

The fry should hatch within 4 to 7 days and in about 2 days you can start feeding them very small bit of the adult’s food.

You can also feed them hard-boiled egg yolks during the first days.

The fry shouldn’t be placed together with the adults until they are big and strong enough to survive in the main tank or pond.

This means they have to be strong enough to avoid being dragged into the filter and larger than the adults’ mouths, as to not be eaten.

On a final note

Breeding goldfish takes time and patience, but in the end you will be satisfied with your new offspring.

Have any of you had some success in breeding goldfish?

I would love to hear your story.

Do drop a comment below and share your experience.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.