Oscar Fish keepers sier:
The eggs normally take 3 days to hatch. If they are fertilised they should turn a lightish tan colour. If they stay white, they are not fertilised. You may notice the Oscars appear to eat the odd egg, this is exactly what they are doing. They know a bad egg and will remove it straightaway. Don't be surprised if you wake up in the morning and all the eggs have gone. This is very common and happens more often than not. Various things contribute to this happening such as eggs that are not fertilised or parents that have been spooked in some way.
Deres artikkel om oppdrett av oscar