Help! What’s wrong with our fish?

I don't know what's wrong with our goldfish, I noticed some white spots on it a few days ago and I didn't think anything of it and now this evening it's full blown literally all over the fish.

I don't know what's wrong with our goldfish, I noticed some white spots on it a few days ago and I didn't think anything of it and now this evening it's full blown literally all over the fish.