Cajunrider
Imperial Masterpiece
Nothing like proven experience. I had a winter kill in my 3 ft deep pond in Ohio. That was why I suggest deeper pond.Nope, 3ft is just fine and the 20 years they were in 30in deep water before this redo proves that. You only need 18in around here for winter protection.
https://www.aquascapeinc.com/water-gardening/how-to-keep-your-pond-fish-alive-during-winter#:~:text=There are several issues to,in order to overwinter successfully.