hey all mfk members! me and my dad are going to build a pond in our back yard. its going to be about 5000-6000 gallons. its going to be a utdoor pond but i would like to keep tropical fish in there too besides only koi. i live in california and in the summer it gets hot. would it be okay to put tropical fish in the pond for the summer and then take them inside for the winter? plus i would like to have a pond heater can anyone tell me where to get one? website, store, etc.....