Building a new pond

[colematthewmalaka]

Hi, spring is almost here and I want to dig a new shubunkin pond in my yard, right now I'm using a old bathtub put in the ground but it's frozen solid because of our cold Canadian weather. I just want to know how deep it should be and if there's any way to keep fish in a pond during the winter here in Canada.

P.S. What kind of pond lining should I use?