I would give goldies at least 3-4 weeks, they really are not a good choice. when coming from an LFS feeder tank, they stand a good chance of bing diseased.
Even When they are disease free,They lack a lot of things, and provide far too much fat, cartiledge etc. Gut load them with some good prepared food right before you put them in with the dempseys. My personal reccomendation is try guppies or rosy reds next time. They are much better for your fish.
Dave