WASHINGTON HAS BEEN GOOD TO Spunky these past 21 years. There's been food aplenty -- lots of yummy sushi and salad -- just there for the taking, not to mention the admiration of a steady stream of visitors. But, alas, living quarters at the National Aquarium have become a tad cramped for the 3 1/2-foot green sea turtle, so Spunky will be leaving at the end of the month for a deluxe retirement home in Florida.

But first, a retirement party, on August 28.

"A lot of local kids will be there, and we're giving a prize to the one who comes closest to guessing Spunky's weight," says curator Michael Bailey, hoisting Spunky onto the edge of his 3,000-gallon concrete tank in the basement of the Commerce Department. "He has a very laid-back personality and everyone here loves him."

Spunky is on his best behavior today. There's no splashing or thrashing, and the parrot-beaked reptile seems to relish having his head and shell stroked, sort of like a contented border collie with flippers. But watch out.

"Don't put your hand too close to his mouth," warns Bailey. "He might confuse your fingers with squid. Sea turtles consider them food."

And what else does Spunky like?

"Oh, spinach and gelatin -- kind of a spinach Jell-O -- raw fish, Sea-Tabs vitamins and Purina Trout Chow. Even broccoli. Two of his favorites are smelts and romaine lettuce," Bailey says. "Spunky is a bottomless pit -- he averages about five pounds of food a day."

Spunky's new digs in Florida will be at the Clearwater Marine Science Center, where he'll have the companionship of other sea turtles in a 50,000-gallon tank. He couldn't be released into the ocean because his origin is uncertain, and biologists are loath to have the endangered animals' gene pool diluted by interbreeding.

Sea turtles can live out of water for four to six hours, so Spunky will be wrapped in wet towels and flown to Florida in the pressurized cargo hold of an airliner.

"Our director, David Gross, will be flying along with him. I wanted to go, but we drew straws, and I lost," Bailey jokes.

Will Bailey ever get to visit his old buddy?

"Oh, sure. I go to a conference at Clearwater every March," he says. "Since sea turtles can live to be 100 years old, I expect to be visiting Spunky for the rest of my life."