John Bossie tried Roach Motels. He tried Combat. He tried an exterminator.

Finally, in desperation, he took home a gecko.

He has not seen a roach since.

The ferocious little lizard that barks like a dog and has feet like suction cups is a natural predator of roaches. And it is a natural ally of New Yorkers who don't mind falling asleep to the sound of scurrying and crunching, scurrying and crunching.

"You almost never see them, but you'll hear them bark," said Mr. Bossie, a manager of Looking Glass Aquariums in Flushing, Queens. "It's almost like they're calling out: 'Gecko! Gecko!' "

In Broadway Aquarium and Pet Shop on Amsterdam Avenue recently, the last gecko in stock was wedged forlornly between the tree frogs and the green snakes. "I had a girl in here whose apartment was so infested she bought two," said Steve Haiduk, the store's owner.