UV in flies

[Bruce Norikane]

I get the impression that uv can genuinely increase the effectiveness of a fly. Is it so good that one should consider using it almost all the time? Any flies that you would for sure NOT use it?

Without getting all spectrum analyzer technical about it,

To a trout, UV is just another color like blue or green. Some trout food has the UV color and some doesn't.

So sometimes the trout will eat a fly with UV, and sometimes they won't. Just like a yellow fly or a purple one.