Q: “Lefty, what is the most effective fly for permit?”
A: The short answer is there isn’t a best permit fly. Different conditions and environments and the size of the fish dictate what is an effective fly. What have been effective for some Florida Keys guides are painstakingly tied replicas of the crabs eaten in the local area.
One reason the Merkin has been so effective is that it doesn’t look like any specific crab. I remember opening up a bonefish that was bitten by a shark and finding nine crabs in its belly — almost none of them looked alike.