this is typical. when a new tank is started, there will be an ammonia spike before the bacteria can grow to eliminate the ammonia. this is a process called "cycling". it normally takes 2-4 weeks to cycle and stabilize a tank. With goldfish, it should prolly cycle in about 2 since they are dirty fish.
you can do a 25% water change every 2 or so days over the next week and that should help alot but it really is just normal. Does your filter have carbon in it? if not, try and get one that does and that will help too.
another cause of coudy water is overfeeding of the fish but this takes time to develop and since your tank is only been up for 3 days, this would not be the case.
do the water change so that the ammonia level will drop a bit and within a few weeks, it should clear up. I am 90 % certain that the ammonia level is what is clouding the water for you.... it is natural at startup.
Graffix will prolly pipe in here at some point since he knows about tanks altho I think he is more reef oriented. I started my freshwater tank in december... a 30 gal tank
Check this site out.... the forum is pretty good and there is some good info there.
E-fishtank