Goldfish's Reproduction

Breeding Goldfish

Goldfish mature at about 1 yr; however, they are in their prime about their 3rd year. A male that is ready to spawn will usually have tubercles about pin size that appear on the pectoral fins and gill covers. However, this does not always occur and has been seen in some females. (see photo of tubercles on male fish)

Temperatures should be about 700F. during the day and 500F. at night. You will notice the spawning chase occur. The male will begin chasing the female for two to three hours, bumping into her abdomen. If she is ready eggs will spurt out and stick to the first thing they come in contact with. They are usually released in batches with the first batch being the best. The male fertilizes the eggs immediately by spraying milt over them. Good sized females can lay anywhere from 500-1000 eggs a spawn.

Goldfish usually spawn in warm waters in the morning sun

You should remove the eggs immediately and rinse them in a bucket of aged water that is the same temperature as the tank they were removed from. Your goldfish eggs should be kept in water that is not deeper than 6 inches. In deeper water the pressure can damage the fry and make it hard for them to reach the surface. After rinsing the eggs place them in a 20 gallon tank. You should raise the temperature to about 700F. The fish will hatch in 3-4 days. By the end of the first day you will notice that some eggs are clear tan to yellow while some are white. The ones that appear almost clear are the ones that are fertile. The others are more than likely infertile and will be subject to fungus. The fungused eggs should be removed immediately, or the fungus can spread to kill the other eggs.

Some breeders add a few drops of methylene blue to the water to cut down on the fungus occurence.

The fish will hatch out along the region of his back, pulling his tail out first, then moving it to release its head. At birth the fish is about a 16th of an inch to an 8th of an inch long with two black eyes, a long notochord, and a full yolk sac. These transluscent fry should not be disturbed. Do not be alarmed if they fall to the bottom. Within 48 hrs of hatching they will have absorbed their yolk sacs and an air bladder and rudimentary pectoral fin will become noticeable. After about 48 hours they're air bladders will fill and they will start swimming normally seeking food. They will eat anything they can fit into their mouths. This is when it becomes important to have some food on hand.

See chart below for feeding instructions

Feeding the babies can be somewhat troublesome since they are so small. You must be sure to place enough food in the water that they can find it, but no too much to pollute the water. Keeping a continous supply is needed. It is best to remove the uneaten food within a few hours and add more. Doing this helps maintain the water conditions. These little guys will grow rapidly and soon be requiring a lot of food.

As the fish grow you will need to place them in larger tanks or divide them into tanks.

Feeding Schedule for Babies

The following shedule is one that I have found and seems to be recommended:

After 48 hrs Crushed yolk of hardboiled egg and oatmeal paste, or there is a liquid available commercially
After 2 weeks Baby brine shrimp and infusoria
After 3 weeks Powdered foods can be used
First 4 weeks Feed 3 times each day
Up to 4 mths Feed 2 times each day
After 4 mths Once daily

(Feedings should be as much as they can eat in 20 minutes)

You should always siphon off any uneaten food, but be cautious so you do not siphon your fish. Once a month a tablespoon of salt should be added to the tank. Artificial aeration can be provided after 1 month.