I have no fish in my pond, though there are plenty of frogs. The frogs have survived severe periods of frost and thick ice for the past two Winters. I don't make any attempt to break the ice. This is what it looks like now..
What's happened is that about 5 inches of snow has fallen onto the water. As the water was relatively warm, a lot of that snow has melted, and that melted snow has formed into shallow sheet of ice. It's not very hard at the moment.
The three 'islands' of snow are places where water lilies are situated.
The things sticking up through the snow around the sides are leaves of water iris.