Well, UV photography can help you be successful doing that!
If you ask why, the simple reason is, that the scientific work on fish vision tells us that fish (some) have four receptors in their eyes, one each for blue, green and red (as we humans have) plus they have a forth, UV sensitive one!
I have been contacted by someone who wanted to find out, why some artifical flies work so very well, when some others don't at all. He sent me a package of very different ones, to test them out using reflected UV photography.
Lens used was my calibrated for UV X35 lens plus for the UV shot the Baader 2" U-filter. Light source used was my high power UV flash system.
So 'nuff talked, lets see some results! [click on image to see larger images]Here now the comparison shot, the visual shot and the UV shot. VIS first then UV (color versions - UV has no color, so ignore that please!!)
and here the black and white version of above for easier comparison of the different reflection patterns these flies have. VIS first, then UV:
It gets quite obvious, that a bright fly in visual light does not necessarily have a high UV reflection. Compare for instance the two leftmost flies in the top row. That artificial prawn left is highly reflective in visible and UV light, but the same light fish like fly one to the right is not at all in UV! But if you look at the bottom row, that dark two-colored fly (2nd from the right) is very bright in UV!
Stay tuned, more will follow on that fascinating subject...
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos