The cold weather has frozen the top of our pond. The fish keep swimming under the top layer of ice, but we have to keep breaking holes through so that some air gets in and the waste gases get out.
Really, the fish more stay really still rather than truly swimming. I actually thought they were frozen in place until they moved really quickly as I started whamming on the top of the ice to break a hole through.
And the fish aren't the only thing that has a protective layer between them and the environment. Since the weather has gotten colder Tovina has also grown a thicker protective layer.