If you wake up to discover your pond has frozen, the one rule you must follow is – never smash the ice. Smashing the ice will effect any wildlife or fish you have in the pond. To brake the ice gently place a saucepan of hot water on top, keeping hold of the saucepan all the time and in a few moments the heat would have melted a circle of ice, therefore allowing oxygen into the pond.
To prevent the pond becoming frozen in the first place, place a large football in the water or partially fill large plastic bottles. In the bottom of the large plastic bottles place a few stones, this will help it float in the water rather than on top of it. The movement of the ball and the bottles will allow a section of the pond to not freeze.
Fish will go into hibernation and move towards the bottom of the pond. The fish may look like they are frozen in the ice but they will be safely at the bottom.
Ahead of any frost arriving remove any pond fountains or filters, unless you have koi carp, and take time to remove any fallen leaves and foliage. Remove any water lilies to a sheltered spot in the garden until Spring arrives before returning them to the pond.