I live in cen cal too. The weather is too cold to have pacu living outside during the winter. I do have a about the ground pond for my koi fish. You should think about getting a 300gal rubbermaid stock tank. You can move it inside in the winter and outside in the summer. It should cost you a little more or about the same as building one. Any bigger gal. size tank than that will be hard to move around.