When TV fishing star Jimmy Houston buzzed through town last week for an appearance on the "Today Show," he wore more gold than Tammy Faye Bakker and was full of good-old-boy wit and wisdom.

"See these worms?" he told a group of D.C. school kids at West Potomac Park. "They're nice and wiggly now, but what about if you fish in the winter?

"Children, if it's cold outside you just have to put your worms in your pocket so they don't freeze, and if it's real cold, pop 'em in your mouth to warm them up."

It was a joke, of course, but the kids never cracked a smile, so intent were they on dunking their worms in the Potomac. Houston's wiggly nightcrawlers soon attracted sunfish aplenty and the bobbers on the little kids' lines started plunging. A couple of largemouth bass even joined in.

"This," said Houston, admiringly, afterward, "is quite a river."

If he thinks the river's good, he ought to see our tourist attractions.

Houston had a plane to catch and didn't have time to explore, but watching those kids catch frisky bluegill sunfish reminded me of a downtown fishing hole I'd heard about for years and had been meaning to try.

That evening, I called Phil Million, public affairs officer for the U.S. Fish and Wildlife Service, and asked if he was still fly fishing the lake at Constitution Gardens early in the mornings.

Million was evasive and dissembling, which I took as a yes. After much prodding, he finally agreed to meet in the morning.

It's a funny feeling to get up at 5 a.m., pack your fly vest, fly rod, camera and canteen and come charging straight into the middle of downtown for a wilderness experience. Happily, the parking spaces at 20th and Constitution were all vacant and from there it was just 75 yards to the lake, trying hard not to wake sleeping homeless folks on the way.

I carried a graphite, 8-foot for 8-weight fly rod and an assortment of cork and deer-hair popping bugs, marabou streamers and whatever else was lying around the house.

The lake, which sits adjacent to the Reflecting Pool alongside the Vietnam Veterans Memorial, was inky black on the overcast morning; a few wild mallards paddled around, tending flocks of young.

Out in the middle was a grassy island connected by a wooden causeway, which looked like a good place to start, since Million wasn't there yet.

Constitution Gardens is a triumph of urban lake-making, a shallow, concrete impoundment whose life-sustaining qualities come from some mud trucked in from the Anacostia basin and some aquatic grasses planted therein. The grasses and mud provide food and shelter for ducks and geese and for the few fish that were stocked years ago, which have multiplied into many.

All this was the idea of the National Park Service's resident wildlife scientist, John Hoke, who also promotes rooftop marshes for skyscrapers in New York City.

I flipped a green, cork popper out near one of the planter boxes in this mid-city aquatic jungle, twitched it a time or two and was satisfied by the attack of a bluegill, which slashed at the fly but missed. It was the start of a fine morning.

I became so engrossed that when a jogger happened by and called out a question, I got all flustered. "Are you just practicing," he said, "or are there really fish in there?"

This is when you're supposed to set the hook on a big bass and astonish the visitor, but all I did was miss a nice strike with great fanfare, at which point Million turned up and offered the advice that, "You're supposed to fish with fly line, not wear it."

He had some little black cork poppers that drove the bluegills wild and even induced strikes from a few largemouth, one of them keeper-sized.

But Million was full of worry. A story in the paper a few years before hinting about fish in Constitution Gardens led to a crowd of eight or 10 anglers the next day and for a few weeks thereafter, he said, and the fishing hadn't been good since.

This was puzzling, since about every time we tossed a fly out, it was attacked.

Anyway, Million was concerned that if people piled in, either the lake would get fished out or the Park Service would declare fishing a public nuisance and ban it.

As it was, he said, Park Police generally disallowed fishing during the day, when tourists were around, on the grounds someone could get hurt on a back-cast.

Million and his colleagues from the Fish and Wildlife Service, which is just across the street, therefore fish before work and leave before the first tourists show up. They rarely keep any fish, returning alive anything they catch.

Since this seems a harmless and rewarding diversion for city folks, one wonders why the Park Service couldn't write simple regulations like: "Sportfishing at Constitution Gardens is permitted daily between dawn and 8 a.m., using flies or lures with single, barbless hooks. All fish must be returned to the water."

Jack Fish, who heads the Capital Region's National Parks, said it sounded reasonable to him, if regulations ever become necessary.

Meanwhile, the bluegills are swarming in Washington's own little farm pond, and practically no one is fishing for them.

This is high season for sunfish, which means a perfect time for parents to take their kids to the nearest lake or slow-moving creek.

Sunfish spawn in the shallows in May and early June. To catch 'em, get some nightcrawlers, small hooks (size 8 or 10), split shot, bobbers and light fishing gear in the 6- to 10-pound test range.

Look for weedy, brushy shallow areas and dangle the worm under a bobber there, near the bottom. When the bobber goes down, you've found 'em.