Breeding Goldfish

[Frasier]

My Wifes 92 year old grandad has got some goldfish in a 2 foot aquarium which he gets a great deal of enjoyment out of and i help maintain. The goldfish have been in the tank for about 18 months when they were brought in from the small garden pond. One of the fish has a very large stomach but thin tail. I have done a bit of research and having looked at pictures think the fish might be pregnant. I have eliminated diseases such as dropsy. I have tropical fish but have limited experience with goldfish, particularly breeding. How long is it before the eggs are released? Is it best to separate the fish? Will they lay eggs on plant leaves or is it best to buy a breeding mat? It would be great if the fish is expecting and any advice would be gratefully received.

 

[Colin_T]

Female goldfish are usually fatter than the males. Males are slimmer and develop small white lumps on their pectoral (side) fins and their gill covers (cheeks) when in breeding condition. They normally breed when the weather warms up after a cool spell. In a pond the water will get cold in winter and as it warms in spring, the fish come into breeding condition. In an indoor aquarium the water is often warm all year round and this can prevent the fish coming into condition.
During breeding the males chase the females around the tank and nudge their belly. If the female is ready to breed the fish will swim side by side into some plants and scatter the eggs and sperm. The eggs sink to the bottom and the hatch after a couple of days. The fry (baby fish) are free swimming a couple of days after that.

 

[Frasier]

Thanks for your advice. I will keep you updated.

 

[Tokis-Phoenix]

I have to warn you, that although the goldfish may spawn, the chances of any fry hatching out and surviving are very slim as goldfish will eat their own eggs after a while if they can find them, and they will also eat any fry that hatch out.