This is too cool not to post up...
Gliding silently beneath the waves they turned vast areas of blue water to gold off the northern tip of the Yucatan Peninsula .
Sandra Critelli, an amateur photographer, stumbled across the phenomenon while looking for whale sharks.
She said: 'It was an unreal image, very difficult to describe. The surface of the water was covered by warmand different shades of gold and looked like a bed of autumn leaves gently moved by the wind.
It's hard to say exactly how many there were but in the range of a few thousand.'We were surrounded by them without seeing the edge of the school and we could see many under the water surface too.
'I feel very fortunate I was there in the right place at the right time to experienced nature at his best.'
Measuring up to 7ft (2.1 meters) from wing-tip to wing-tip, Golden rays a re also more prosaically known as cow nose rays.
They have long, pointed pectoral fins that separate into two lobes in front of their high-domed heads and give them a cow-like appearance.
Despite having poisonous stingers they are known to be shy and non-threatening when in large schools.
The population in the Gulf of Mexico migrates, in schools of as many as 10,000, clockwise from western Florida
to the Yucatan .