I recently started a gold fish tank. I bought a black moor which has turned white!
I also bought this weekend a orange and blacl oranga...it is turning completely orange and his head is turning white.

Does anyone know what is going on??? Please help

Some color changes are normal. Read these sections on my site:
http://www.fishpondinfo.com/gfish4.htm#health under color changes
http://www.fishpondinfo.com/gfish3.htm#change

The question is whether the changes you're seeing are normal. Photos would help. True black moors normally stay black or turn brown. To turn white seems extreme but if the "black moor" was not purebred, it could be possible. For an orange and black oranda to change to orange and white sounds like a normal transition for young fish but this should occur over a few weeks. If it occurs in one day, then it's more likely an indication of something being seriously wrong, normally water quality or even poisoning (including high ammonia). Be sure to check your pH, ammonia, and nitrite levels to be sure they're ok. How big is your tank and how long has it been set up? How big are the fish? Smaller fish are much more likely to change color as they grow.

Thank you for responding. I have a 30 gallon tank, which has been set up for about 4 months. I have a penguin bio wheel on the tank.

The black moor which is white is only about three inches long.

My orange and black oranga is 5 inches. He is pretty big. I only had this one for a week and already I can tell he is changing color to an all orange color. I do not know what to do at this point.

I read that goldfish like high ph water (mine is about 7.4) and there isn't ammonia problem. I do not know how to check for nitrates.

I have three fish all together. What am I doing wrong???

I don't know that you're doing something wrong. The color changes may be normal. Black is often a transitional color that later goes to orange. If you could post a photo of the fish in question, I should be able to tell you if the color change looks normal or not. Goldfish don't like high pH, just 7-8 is fine with 8.5 starting to be high.