What kind of fish????
It sounds like natural iredescent coloring to me, I'd need a pic(or at least the type of fish!) to tell for sure.
In either case, I'm highly doubtful it is ick; ick looks like grains of salt or suger; tiny white bumps.
EDIT: After reading your sig, I'm assuming it is a guppy; shiny spots(iredescence) is perfectly normal, and very common, on guppies. It is also common for them to develop it later in life, so it isn't strange that you didn't notice it untill now.