Re: best crappie fly ?
Have a few colors handy. Some light, dark, and neutral.
Where the critters get picky is with depth and speed. Vary the speed. I've seen them go from chasing bass lures to just barely ticking a 1/32 oz stationary jig. When they are sluggish they will eat something in front of them, but won't move a foot to get it. In general, they also feed "up". Get a fly under them and they won't see it.
This time of year, look for rip-rap or shallow brush near deeper water. They can get really shallow. If no takers, start backing out and fishing deeper. They tend to bunch up and suspend. Find the depth and you're in business.
I use floating lines and short mono leaders for the shallow ones down to.about five feet. After that it's sink tips.