Sorry to hear you aren't happy with the color change of your clowns.
Many fish change colors when they transition from juveniles to adults. And some have different colors while mating as well. This is all normal.
But the clowns have had so much genetic manipulation over the last decade or so that those mix of genes are finding their way into the regular gene pool for these fish. And not always in a way that we want. Some of the manipulated breeding types are here:
http://www.orafarm.com/products/fish/clownfish/ You could have some mix of the mocha or the caramel clowns, the adult colors on both these are darker then when they were juveniles.
Even my black and white clowns were mocha in color at 5 months old and are now solid black and white (the male still has a little orange on the mouth).
5 months old