If the water temperature gets that high and stays that high long it is unhealthy for your fish and you should consider landscape changes to provide shade for the pond during the hottest parts of the day. Reguardless of whether or not you've had fish 'survive' those temperatures in the past it is unhealthy for them and eventually will lead to their death.
Slightly off topic, but:
There is a world of difference in living and simply surviving. I would personally not like to merely survive, I want to live while I'm alive, if that makes any sense?
I hope that explains my stance on living versus surviving, and I hope I made my arguement for the facts of health and temperature being directly related with fish clear and understandable.
