My father and therefore are almost done establishing our 200gal pond outside (father just want's to perform a little more of stone try to hide the waterfall weir better). It's a little more then 3' deep and My home is the San Fernando valley and so i know I do not need to bother about water-feature freezing in winter however it does get pretty cold sometimes during the night in December and The month of january (40-50F). Summer time will get really hot too but we selected the best/shadiest place for water-feature to ensure that should not be considered a problem.

I have read that Ryukins and Fantails are more durable then other fancies, but my local seafood shop got some Panda Telescopes that i'm just deeply in love with and that i do want some for water-feature. So essentially can i require a heater or will the warmer bottom water have them with the winter nights?

Also it is possible to way I possibly could make use of an extra aquarium heater to warm-up water-feature rather than obtaining a new Pond Heater basically need one?