But there's more to it than that. The fly fisher studies the aquatic environment, learning what fish are there and what they feed on. The catch phrase is "matching the hatch," according to Dusty Wissmath, director of the fly fishing school at Whitetail in Mercersburg, Pa.
Flies - or lures - are "tied" or made from a variety of things - including natural materials such as hair and fur and man-made items. O'Keefe, whose calling card promotes his flies and lures as "unique," has used medicine bottle tops with tiny rolling eyes glued on. Being able to fool the fish into biting at something that's not real is satisfying for the angler, Gilford says.
For Wissmath, having the fish go for the fly you've designed sort of completes the circle of constructing the fly, casting the line and hoping.
The difference between fly fishing and other kinds of fishing is in the line, Wissmath says. In fly fishing, the line is what has the weight. The fly itself is virtually weightless. Different weight lines are used to catch different size fish.
You don't cast the lure or bait in fly fishing.
"You actually cast the line," Wissmath explains.
No physical strength is required for the sport, Gilford says. Another pleasant feature of fly fishing is that casting itself is graceful, Gilford adds.
"The line moves by unrolling."
The sport has been growing in popularity in recent years. Gilford cites a Wall Street Journal article about eight years ago that counted fly fishing among the top 10 yuppie hobbies. He credits the 1992 film "A River Runs Through It" with a one-year 500 percent increase in his sales. That leap tapered off, but he still calculates a net gain of about 20 to 25 percent because of the movie.
Although fly fishers are not against eating fish, many support catching and releasing them to help preserve fish populations, Wissmath says.
"It's an excellent way to get more miles out of our natural resources," Gilford says.
O'Keefe says that some fly fishers protect the fish by pressing down the barbs - the sharp part of the lure - or using barbless hooks.
Do fish that have been caught and released a few times get harder to catch?
"Oh yes," O'Keefe says. He adds that he and his fellow anglers joke that by the second week in Big Hunting Creek near Thurmont, Md., all the fish have Ph.D.s.