A fly fishing setup is different from spin-bait. For spin bait, the bait provides the momentum to carry the line during a cast whereas with fly fishing, the line carries the momentum since the flies are so lightweight.
You want to be sure to get a tippet line though, not a leader. Fly fishing leader lines are tapered, so they will be thick on one end and thin on the other. The Tippet is a uniform, but very thin material that is also quite strong. The tippet, being so thin, won't have a lot of memory, so it shouldn't coil up on you (unlike spin bit fishing line).