Green water is the formation of green algae in the water, usually due to the tank's exposure to moderately intense natural sunlight. Although some aquarists dread it, as it tends to be cloudy and obscure the view of the fish, some people enjoy it because it has wonderful health benefits for the fish. You can search the forum and find out much, much more about it (as well as how to make it).
I doubt there's such a thing as orange water, hehe.

!