TAKE ONE three-pound fish.

To Paris.

That was the hope of two T dozen American-based chefs when they entered the first U.S. preliminaries for the Prosper Montagne' Culinary Prize, a prestigious French cooking contest held in Paris each January.

Take one fish -- a sandre in France, trout substituted in the United States -- and accompany it with one green vegetable-based garnish, one starch-based garnish and one puff-pastry barquette.

That was the challenge issued to the contestants, who were required to be working chefs between the ages of 25 and 40 years, to devise their own recipes and to write them in French.

Gerard Vettraino, chef of Jean-Pierre restaurant, filled his barquette with leeks and scallops, topped his semolina and mussel savarins with stuffed crayfish bodies, and set his fish in a pool of red wine sauce swirled with nantua sauce. That won him 275 points and first place in the U.S. cookoff Dec. 6, where the six finalists prepared their dishes to be presented anonymously at 15-minute intervals to a jury of 11 chefs and one head of a gastronomic society.

Tino Buggio, sous chef at Maison Blanche, was 3.5 points behind Vettraino and second-place winner, having poached his trout in white wine and beer, decorated asparagus flans with treble clefs made of his tomato and cream sauce, and filled his barquettes with roquefort cheese, belon oysters and red bell peppers.

Red bell peppers might as well have been a required ingredient. Gerard Tasso, associate chef of Le Lion d'Or, the third-place winner, also used them, in his border of duchesse potatoes and in the souffle' topping for his trout. Like Vettraino's, his creation employed crayfish; like Buggio, he seasoned his dish with basil.

Crayfish, mussels or oysters as stuffings; basil, red bell peppers, saffron or fennel for seasoning; spinach, artichokes, zucchini or asparagus as green vegetables -- they were repetitive themes in these elaborate presentations.

But the six finalists showed how far one could wander when instructed, "Take a fish." Vettraino perched his fish on a fried bread boat. Tasso stuffed his fish from the top, with souffle's of red bell pepper pure'e and avocado. Underneath were fine noodles, pine nuts, spinach, mushrooms, fennel and basil. Buggio's starchy accompaniment was ravioli stuffed with mussels, spinach, cheese and mushrooms. Francis Pradier, sous chef of Le Lion d'Or, combined spinach with pears, and made tiny potato cakes topped with a swirl of fresh cheese. Pierre Chambrin, executive chef of Maison Blanche prepared marrow custards, and stuffed cucumber cups with zucchini. Andre' Gaillard, the only finalist from New York, the executive chef from the Perigord Park, stuffed his trout with its own roe and sauced it with watercress, a safe route that led him to last place among the finalists.

The local competition was the first project of the newly formed U.S. chapter of the Club Prosper Montagne', headed by Jacques Blanc (formerly of Le Provenc,al and now about to open his own cooking school in the District). He negotiated with the president of the 30-year-old club in France for the American winner to be automatically admitted to the finals in France. But the winners until now -- in fact, all of the entrants until now -- have been French-born. What if an American won? asked Blanc. "You are going to create a revolution," Blanc reported the president, Andre' Vrinat, as having answered.

Because the idea of promoting an American entry to the contest in Paris got a late start -- only about three months ago -- the first task for the committee was to order the trout; a half-dozen three-pound trout can't be bought on a moment's notice at any local fish shop, but must be specially raised. Raising contestants was an even more complicated job; given such short notice, most of the entrants were from Washington. But the dozen judges included Jean Banchet from Illinois' Le Franc,ais and Le Mer restaurants; Raymond Vaudard, a retired chef living in New York; Georges Perrier of Philadelphia's Le Bec Fin; Jean-Jacques Dietrich of New York's Athletic Club; Paul Eblin of Richmond's La Petite France and Jean Louis Montestrucq, about to open a restaurant in New Orleans. The rest were from Washington: Jean Louis Palladin (Jean Louis), Doug McNeill (Four Seasons), Bernard Binon (Mayflower Hotel), Bernard Campagne (La Bergerie), Felix Veirun (Hotel Washington) and Robert McDaniel, the only non-chef.

Vettraino will be off to Paris at his own expense in January to repeat his recipe -- this time with no trout. The contestants will be using sandre, a French fish, instead.

He accepted his award without a smile, commenting only that he looks for difficulty in preparing for a competition. "Easy things don't pay off," he said. And he should know, having won several other prestigious medals in France. "But sometimes nobody understands," he added quietly. And after this contest? Two or three more competitions, predicted Vettraino, who has been in the United States for only a year and a half since coming from Monte Carlo to take over the kitchen of Jean-Pierre. "Then I will take time to study English.