So I have my pond up and running and am wanting to introduce some fish to it. There's already 10 goldfish that stayed in the pond over the winter, but I have 2 more in an aquarium that haven't yet been in the pond. Generally when I introduce fish to the pond, I wait until there's very little temperature difference. However due to circumstance, it will be easier on everyone if I can get the fish introduced as soon as I can.
The temperature of the tank is approximately 20C (68F) and the temperature of the pond is about 12C (54F). Can I simply float the fish for an afternoon to let them acclimate? Or is there a maximum amount of temperature change that they can handle in a day? Any info, tips, or strategies would be much appreciated. Cheers
(I attached a picture of the pond mostly to show it off. The garden around it doesn't look great yet this year but just look at that water

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