We had some problems with this as well as our climate does not allow for one species of fish. Basically we resorted to Koi. My setup is in a greenhouse that is unheated and the water temps soar in the summer time and plummet in the winter. Koi can withstand all of this.. from 0 deg right to 40deg C. Problems you will find here is that during winter without supplementary lighting and heating the tank/greenhouse.. you will not grow much.. we tried last winter with no success and summertime temps without a chiller or buried FT make it impossible to do trout as they can handle 25 deg max and are not truly happy at that temp. Ideal would be around 17 for good active trout.
Another problem with koi over winter is you can not feed below 10 degC as they will not be able to digest food and will get bloat and die.. no food = no nitrates. Also the bacteria in the nitrogen cycle slows down to a crawl below 13 deg C (feed is minimal as the bacteria may not be able to keep up with heavy feed/stocking density). With all this being said if you have a way to heat and maintain temps at 15 deg over winter trout would be a great cool weather choice (if you got 3 to 6 inch fish and overwintered to harvest size by early summer) and during the hot months of the summer koi would be better option unless your willing to fork out money for a chiller. All these things = money when paying for electricity. Basically for us over the winter the koi just go dormant and sit on the bottom and we forgot about them for 4 months.. They are just starting to come back to the surface for food now. No you cant eat them but they sure are pretty to look at..
Hope this helps..
This is my thread
http://www.backyardaquaponics.com/forum ... =18&t=9762 might give you info that i have not covered here.. there is some average water temps and stuff threw out our first year.
