When you've had your goldfish for a while it's normal to think about breeding them. It seems that everyone that has been keeping goldfish successfully goes down this path. Breeding goldfish in an aquarium will require some preparation and attention to detail.
It's not as easy as how you breed goldfish in outdoor ponds. This is because in their natural habitat fish have more, space, oxygen and plants to leave their eggs on.
Let's go step-by-step trough the things that you need to do in order to provide the ideal conditions to encourage goldfish to breed successfully.
It's a fact that goldfish are ready to breed from 1-2 years old, but usually they breed best at 3 years.
They spawn once a month from April to August, when the weather is warmer. Spawning provides a wonderful opportunity to learn more about your goldfish.
How to Sex Goldfish
Sexing goldfish is not as simple as telling the difference between a duck and a mouse. The only way to sex your goldfish is during the breeding season. You must know how many males and females you have before you can start breeding goldfish. Here are the differences:
Female :
- has abdomen swollen
- more rounded than the males (easier to observe when looked at from the top)
- when she is ready to spawn, vent becomes protruded
Male :
- has breeding tubercles or white "stars" covering its gills and pectoral fins
- when he is ready to spawn, the vent becomes more open and longer
The "Chase"
Males start to pursue goldfish relentlessly, creating quite a splash. This behavior is normal, although males may start to appear "aggressive". The chase will continue as the male nudges the female's stomach area, encouraging her to release their eggs so he can release the milt.
The process of external fertilization means that both the milt(soft roe) and the eggs(hard roe) are released from the male and female outside their bodies. Females can lay up to 1000 eggs, though only a small portion of these become fertilized and grown into healthy adults.
Goldfish Breeding Cycle
The process is initiated by the female. She sends out pheromones to let the male goldfish know it's time to prepare for breeding. This encourages the production of milt.
Your male starts to nudge the female and chase to encourage her to release the eggs. He will follow by spraying his milt onto the roe to fertilize them.
Now, breeding goldfish is not that easy. Sometimes knowing how to breed goldfish is not enough. You have to be patient and encourage your fish to start the breeding process.
Encourage Your Fish to Breed: Step-by-Step
- Goldfish are pre-programmed to reproduce when it's warmer. A heater is useful and consistency to water temperature or you can wait till the temperature changes naturally
- Add some protein to their diets. Protein-rich foods like daphnia, insect larvae, bloodworms, brine shrimp should always be used as treats. Also add vegetables and fruit to their diet to keep them healthy and not constipated
- Feed your goldfish 3 times a day to trigger the breeding response
- Fresh water helps goldfish have more energy. Change 20% of the water every day to remove the waste resulted from extra foods
- Keep a consistent water temperature of 70oF(21oC) during the day and 50oF(10oC) during the night
- Sex the males and females
- Separate the males and females into different tanks for 3 days, to create a greater desire to breed. You need to prepare the second tank a week in advance - later this will become the "fry tank" for the young goldfish
- Reintroduce the fish together
- Keep doing daily 20% water changes to maintain water conditions. Always treat the water with purifying conditioner before adding to the tank
- Create a "spawning mop" and add it to the tank you want to breed in. This will help catch the eggs later, so you can remove them to a separate tank, to allow the fry to emerge
How to Make A "Spawning Mop"
In the wild, goldfish naturally mate amongst plants and vegetation. To create a natural environment in captivity you need to create a "spawning mop".
You need:
- a shier(dark green) of acrylic yarn
- a cork(from wine bottle)
- A4-size hardcover book
- pair of scissors
Steps to making the spawning mop:
- Boil the yarn in the water to sterilize the wool and ensure it's not harmful to the fish
- Open the book and put the start of the sting inside it(right behind cover). Remember where you started
- Take the rest of the wool and wrap it about 50 times around the length of the book
- Once you finish Step #3 cut off the sting from the book to the yarn. Then cut of a 5" piece of sting. Tie it together around the middle of the 50 strands of wool. This will keep them together
- Turn the book over and cut the wool around the back right along the middle. This will create 2 equal length strands
- Tie or pin the cork using the loose strand of the wool on the top t allow the mop to float. This will make it resemble the natural plants in the wild
- Add it to your "breeding tank"
The Healthy Female Goldfish
When breeding goldfish, you must know that males can sometimes become "aggressive" towards females, constantly nudging them and forcing them to release the eggs. If this goes on for more than a week, you need to move the females into a separate tank to give them some rest.
This way you can prevent the female from losing too much scales, getting over-stressed and affecting the immune system. You must keep a close eye on them. Good Luck!