when do goldfish breed?

Question
When do goldfish breed?  I have a 1,400 gal pond with about 35 goldfish.  Most are about 2 years old & about 6" long.  However, 5 are much bigger - at least 12" long that I got from a breeder.  About a month ago, were wiggling in the suspended roots of water hyacinths & chasing thru numerous pond plants.  I guessed they were breeding.  But, I didn't see any fry. Today, they were chasing each other again. Are they breeding?  If so, what should I do to keep the fry from getting into the skimmer? Is there anything else I should do? PS Thanks for your advise on the injured fish - it is much better now.

Answer
Goldfish breed/spawn whenever they feel as though the conditions will support young... Usually spring/summer.  It sounds like they may be trying to breed the problems is that goldfish are constant scavengers and once they lay eggs... they usually go back and eat them.  To keep the fry out of the skimmer you would have to make sure that the ponds circulation is not so strong that the fry could not fight against it.  They usually find places to hide until they are older... dave