Are there any potential problems with adding goldfish who have lived in a tank into a pond which already has goldfish in it. They look like different types of goldfish but i'm assuming they'll all get along?
Shoudn't be any problem, so long as you allow the tank fish to "aclimatise" Get a strong polythene bag and part fill with water from the tank, place your tank fish in it fasten up and "float" in the pond for about an hour to let the temperatures equalise then release the fish into the pond. I've got ordinary goldfish, comets & shubunkins in my pond & they all seem to get on OK tho' you might find your tank fish change colour slightly due to the different conditions in the pond