If you have small fish, do them a favor and set up a bowl for them in the house. It’s not going to be as big an area they were used to; but it beats being a “fishsicle”.
A pond has to be at least two feet deep to support winter life. Shallower ponds will freeze solid. Having at least two feet of depth will insure a swimmable environment under the ice.
You may be pondering “How can I feed my fish in the winter? The answer is you don’t. As the temperature drops so does their metabolism. In fact you should be curtailing the feeding program to two or three times a week when the temps drop to 60; and stop it altogether at 50 degrees.
But I write this now because you have a little window of time to do something you should have been doing all summer, feeding them a high protein food in anticipation of this upcoming winter.
If you have the right depth you can over-winter your fish in your pond…maybe. It’s still a crap-shoot. Or you can play it safe by plucking them out before they become entombed in the ice.