Returning Goldfish to Pond
I have a 6" pond goldfish who developed clouding of the eyes. She did not improve with pond treatment so was brought indoors to a hospital tank.
I've reduced the tank temp to 60 degrees but pond temp is 45-50 degrees. I can move her tank to approximate outside temp and over a few days gradually reduce temp to that of pond. Is this OK or should I abandon the idea and keep her indoors through the winter.
She has been raised in the pond and has survived numerous NW winters.
I'd appreciate your advice.
Personally, with the pond temperature as low as it is, I would keep her inside for the winter.
The reasoning behind this is at temperatures below 50F, Goldfish are either hibernating or are in a low metabolic state. They are eating very little and are surviving on fat reserves built up over autumn.
You didn't mention how long she had been inside recovering, but what are her fat reserves like?
If you put her out now with low fat reserves, she will use whatever she has over the winter and be in poor condition come spring. Many Goldfish die in spring after successfully surviving winter because their fat reserves were too low in autumn.
Another issue is any animal, and that includes Goldfish, needs time to adjust from an active state to a semi-dormant state. This should take place over weeks not a few days as body enzymes, especially those in the gut, change depending on temperature.