... shad have quite a few different colors along the top of them, with green and brownish/purplish color being the predominant colors...paint the top with a mixture of brown and purple first... take a forrest green or a dark green (you could even try a light green if you wanted)...spray it over that first coat...bring that green down the sides.
Suggestion related to BB94's idea:
Brown back....mesh...white as base...then purple...remove mesh. Light coat of iridescent green over the back ending above the lateral line...detail accordingly. I like BB94's idea...may try it on PVC to see how it goes