Now I know it's strange but...my dad doesn't want me to dig in our backyard. Yet, I NEED a pond for my 7-8 inch koi. People tell me that a kiddie pool would do fine but what about stray cats? And how would I filter it? Oh...big issue...I live in Arizona...where it gets HOT. Would it be okay for him? After all, I want only the best for my fish...Please, please help! (sorry for so much questions, hehe)