FLY FiSHING Knots
Knots are essential in fly fishing rigging. In a typical fly fishing rig, knots are used to attach an artificial fly to the tippet, the tippet to the leader, the leader to the flyline, the flyline to the backing, and the backing to the reel. For each of these connections, there are many different knots one could use. While many fishers take great pride in mastering the tying of all the knots used in their fly fishing rigs, fly fishers do not need to know them all.
After 40+ years of fly fishing, I've can probably count on one hand how many times I've had to connect backing to the reel or a fly line to backing... and never have I done so on the river. I've always tied done so in the comfort a home or cabin with access to a cheatsheet or the Internet to refresh my knowledge of the seldom-tied knots. I often rely on professionals at the nearest local fly shop to tie specialized knots used for these connections.
Fly fishers need to master just two knots: a knot to attach an artificial fly to tippet and a knot to attach tippet to a leader. For the former, the improved clinch knot will do. For the latter, a surgeon's knot will do. Only after mastering a knot for each of these purposes should you consider learning a new knot.
As we often use loop-to-loop connections in fly fishing, be sure you master that connection as well. There's definately a right way (symetric connection) and wrong way (one side folded over) to put the loops together.
My everyday knots
For attaching flies to tippet, I typically use the uni knot (also known as the Duncan loop knot or grinner knot). I find it dependable and easy to tie, even in the dark, with minimal material waste. You can even leave the loop open to allow your fly to move more freely. I'll often use the double davy for attaching small flies to small tippet for a less bulky knot.
For attaching tippet to leader, I use the double uni-knot. It seems more dependable than the triple surgeon's knot... though it takes a bit longer to tie.
Useful knots to know
Not that I use them all that much; here's a few more knots that I have in my quiver.
The non-slip mono loop knot is a good knot to know for attaching a fly to tippet with a stable loop (a loop that won't close). If you nymph most every day, you might even consider this an everyday knot.
The nail knot is a useful knot for attaching leader material to a fly line when the fly line doesn't have a loop connector.