Spring is coming

[OldMan47]

OK so I had a stock tank set up through last summer and early fall that I kept fish in. The fish got brought inside when the weather started getting too cold and the tank / pond got drained to overwinter.
Now comes the dilemma. I do not want to wait for the weather to get warm enough that water kept outdoors will stay above 75F before I set up again. I do have goodeids that would be OK down to about 50F and was wondering how people go about stocking in the spring to make maximum use of the nicer outdoor weather. The fish are obviously nicer looking when I bring them into the house in fall but I am concerned about the fish needing to experience a 15F drop in temperature when I move them outdoors. Is there a particular approach that has been used with success to move fish outdoors?

[Nolapete]

A friend of mine has a temporary greenhouse that he puts over his pond in the winter. Granted, our winters are mild, but still too cool to have fish outside. I don't know what temp it keeps the water, but he has his discus out there so it can't be that cold. We've had a lot of days in the 30s lately and he hasn't had any problems with his fish. Once the weather warms up, he removes the greenhouse.

[edh]

I have a pond lined up for this spring as well can't wait to get it in, but I will.

It's 27°F right now in the northwest burbs of Chicago, I figure I will put the pond in Early May and fish by first week in June. Guppies first then a few Plecos later.

[OldMan47]

I am hoping to beat that date by at least a month Ed. I will be putting some goodeids outside and they are much more cold tolerant than guppies. My concern is mostly that the goodeids are indoors now and their tank never goes much below 65F. The sudden drop to 50 is likely to be a bit stressful for them if I am right.

[bluekrissyspike]

maybe add some kind of cooling system to the tank to slowly decrease the temp or add a pool heater to their pond?