Goldfish eggs take about 5day at 21C, 7days at 18C.
To give the fry the best chance to survive you should bring the water
level down to 15cm (so they do not get crushed by the weight of the water).
Once they have hatched they will feed on their yolk sack for about 3days,
When they have finished their yolk sack start feeding them small foods
like BBS, microworms, liquid food, crushed hard boiled egg yolk, crushed flake food, ect...