It looked like the end when they routed Interstate 81 through Charlie Fox's meadow. The new overpass straightened out a fishy bend in the LeTort, but the stream's native brown trout found new hidey-holes in the shade of the bridge. Slowly, things grew back together.

Fox worried when the apartments went up next door and new houses closed in around him, but his tree-tangled seven acres and the 2,000 feet on the LeTort somehow remained undiminished by encroaching civilization.

Then on May 17 a Pensylvania Fish Commission truck roared up "in a cloud of dust," as Fox recalls it. He was enjoying a family picnic. The state man said, "Oh, Charlie, there's a terrible fish kill going on."

Fox, 72, hurried to the banks of the stream that has been his back yard for 30 years. He saw suckers skittering along the surface and throwing themselves onto the banks, preferring to die there than in the poisoned water. He saw trout swimming crazily, diving into thick beds of elodea grass and not coming out again.

He watched this scene of horror. Then the next morning he went upstream a mile to see if he could find out why. He found a six-inch pipe leading out of a commercial watercress bog. "Everything below the pipe was dead," said Fox. "Even the frogs and the worms. I believe that in that stretch immediately below the pipe not a trout, sucker, pointed-nosed daice, sculpin, sow bug, crayfish or shrimp survived."

Later investigation by state officials indicated the cress-farm operators had treated the bog with an extremely potent pesticide called endosulfan, which flowed through the pipe and into the stream by mistake.

The state had run electroshocking tests of the LeTort at Fox's meadow for three years and found an average 550 brown trout per 550 meters. Four days after the kill, they shocked the same stretch and got 44 trout.

"I figure they (the survivors) were the lucky ones that were in musrat holes or way back under the banks when the poison came through," said Fox.

So there's a pesticide spill in Pennsylvania and a bunch of fish die. So what?

Only this: The LeTort, where it runs past Fox's place, is one of the revered trout streams of the East, fabled for the challenge its wily trout present; fabled for its wild, vegetation-choked surroundings. The name LeTort carries with it a mantle of history and tradition. It's a place where the finest fly fishermen have tested their craft, a place that has given its name to fly imitations invented there. It's the spot where a new concept of trout fishing -- the idea of fishing for fun and returning all but true trophy catches -- grew to fruition.

For 40 years Fox watched over the LeTort and turned it into the shrine it is. "I came here because of trout," he says. "That's why I found this meadow and why I bought it, and why I built the house here and lived here. But now I don't think it will be the same again. Not in my lifetime."

Fox has had time to come to grips with the new, barren LeTout, although at first he was enraged.

Last week, calmer, this thin, gray-haired wizard of fly-fishing walked the banks and pointed to places where trout used to lie. "Some of them were like pets," he said.

The poison has broken down and has been flushed out of the stream, but the damage is done and the trout and bugs and minnows and shrimp are mostly gone. The question now is how to revive the stream.

The LeTort has its own breed of brown trout, a cross between German-origin browns stocked early in the century and prized Lock Leven browns from Scotland that Fox purloined after they were stocked in nearby streams. The resulting strain was scrappy and particularly wary, responding only to the deftest angler's approach.

Fox wants future generations of LeTort trout to evolve from the few that are left, to retain this special hybrid strain and keep the challenging nature of the stream intact.

"I've never seen anything like it," said Fox of the difficulty of fishing the LeTort, "and everyone who comes here says the same thing." He cited a combination of factors -- the slow flow, making proper presentation of flies critical; the soft banks, which required anglers to creep not only slowly but softly; the abundant food sources, which made the trout more selective; and the thick grass beds, which forced fishermen to fish deep in blind holes when the trout fed on bugs in the undergrowth.

"Because these fish are so discriminating, a lot of the fellows who fish here become dissatisfied with the flies they were using, and that's where the development of new imitations began," Fox said.

Vince Marinaro developed jassids and cinnamon ant imitations on the LeTort; Ernie Schwiebert designed the no-hackle, no-tail, hair-winged hopper now called the LeTort hopper; Eddie Shank tied the same pattern in a cricket and that became the LeTort cricket. Japanese beetle imitations were developed here, and winter fly-fishing for trout had its origins on this spring-fed limestone water that never freezes.

It was all helped along by Fox. He filled in sections with gravel to foster spawning; hauled in flat rocks to expand cover and habitat; planted the banks for visiting fishermen; built casting platforms in the water and benches from which to watch the changing drama that is a great trout stream.

Now Fox is busy negotiating with the state and with private lawyers over how the damage will be undone and who will pay for it. It's not exactly what he had in mind.

It's sure changed my life," he said. "When I retired seven years ago, I figured to spend the rest of my days right here in this meadow, watching the trout and fishing when I felt like it."

Now he watches a wasteland that's out of whack. "The balance has been upset terrifically. If it comes back in my lifetime to even half of what it was, I'd consider that great."