Rescuers were hoping that the 40-ton whale would be swept to safety by the turn of the the tide at 8pm, but feared it was unlikely to reach open waters by this morning.
Charles Bickett, general manager of rescue co-ordinators Deep Sea World, said Moby had at least gone past the Forth bridges, despite his apparent aversion to the traffic noise. He said they would probably assess the situation later today and possibly start a fresh rescue attempt tomorrow.
A flotilla of 11 boats, watched by a growing media pack, was involved in yesterday's rescue attempt, including two tugs loaned by BP. They stayed upstream of the whale, making what organisers described as a "wall of sound" to force the animal out to sea and away from the risky shallows.
Four-year-old Moby was heading from the Arctic towards the Azores - a whale breeding ground - when he became disorientated. Alex Kilgour, the promotions manager at Deep Sea World, said: "They say there is no better place to have a heart attack than in a hospital and Moby couldn't have chosen a better place to be stranded than outside an aquarium."Reuse content