How to spot spawning time:
Female gold fish become heavier and thicker due to eggs.
Male gold fish develop white spot on gills when they got ready.
Spawning usually occurs in the morning.
Color of fishes become more brighter.
Male gold fish chases females at random.
Then particular males chases one particular female more then before.
The male gold fish gets aggresive and push against female gold fish till she ejects egg.
When the eggs are out male deposits milt on them.
Then the eggs fall in water and on plants till they hatch.
The spawning may begin after some days of rest.
Note:The goldfish are egg eaters so remove them after spawning.
Set temperature to 21ºC .Put few drops of methylene blue to prevent them from fungus.Gold fish fries are not needed to be fed till 24 hrs because they have egg yolk sac.After hacthing they will sink to bottom of the tank try not to disturb them .The process of sinking is normal.When sac is absorbed feed them baby gold fish food or hard boiled egg yolk.After it shiphone the uneaten food but not babies.