It may take a few days after temperatures exceed 50 degrees for fish to begin to regain normal functioning and altertness. Once water temperatures exceed 50°F for at least a few days, your fish should naturally regain normal alertness, activity levels, and feeding patterns again. Don't try to “wake up” the fish yourself, as doing so could cause shock, injury, or the usage of precious energy reserves that are still needed until the fish naturally revives itself.
When first coming out of torpor, your fish will display slight movement – not much at first, but this will gradually increase as temperatures get warmer. Your fish won't be grouping together as tightly for warmth, and their fins won't be held closely to their sides. Similarly, their appetite will return as their metabolism speeds back up – usually around 55 to 60°F for koi and a few degrees higher for goldfish.
