jiveturkey once bubbled...
Comparison
Before:
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After:
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This is good, but I think you only added in the red layer. That's only the first step. The second step is to make hue/saturation adjustments as necessary, as well as minor color-balance and exposure cleanups if necessary. Here's what I get if I do this with your picture. See my website if you want to see examples of what I do -- http://www.pbase.com/dkusner/photoediting.
Note that I'm not 100% sure what the colors on this fish are supposed to look like, and without this as a guide I may have gone a little wrong. You should always use reality as a guide.