"Pianos don't grow old gracefully. "

Here's a mystery that gives a whole new meaning to the phrase ``piano bar.''

A grand piano recently appeared on a sandbar in Biscayne Bay, about 200 yards from the Quayside condominiums off Northeast 107th Street. Whoever put it there placed it at the highest point of the sandbar so that it's not underwater during high tide.

How and why the piano got there is a mystery. A grand piano weighs at least 650 pounds and is unwieldy to move, said Bob Shapiro, a salesman at Piano Music Center in Pembroke Park. "You don't take it out there in a rowboat,'' Shapiro said.

This much is clear, however: The piano isn't going anywhere anytime soon. Unless it becomes a danger to wildlife or boaters, authorities have no plans to haul it away.

``We are not responsible for removing such items,'' said Jorge Pino, a spokesman for the Florida Fish and Wildlife Conservation Commission. ``Even a car can become a habitat for wildlife. Unless the item becomes a navigational hazard, the Coast Guard would not get involved.''