This linguistic confusion is why Americans call the Pennsylvania Dutch Dutch even though they're Germans. To review: this country is the Netherlands, its people are Dutch, they speak Dutch. There is no country called Holland, but there are provinces of North and South Holland.
In clean, uncrowded conditions in tanks or ponds, goldfish grow fast. They can grow to a few inches (1 to 4 inches) within the first year. It really depends on their genetics and living situation. It may take a year or two before they change color from brown to gold or whatever color their parents were.
Only about 80 percent of goldfish eggs develop. Remove any that remain cloudy since these eggs are unfertilized and will grow fungi that can spread to developing eggs. Goldfish fry typically take several days before they become free-swimming. During this time, the baby fish live off their yolk sacs.