Can i get goldfish help?

We bought a 50 gallon tank we are using a flu-val 4plus filter, we had 3 fancy goldfish in a 10 gallon tank. we let the tank set up, went and bought 2 more fancy goldfish (mostly as testers) they was fine in the tank, we added our other three 48 hours later now they all lay on the bottom of the tank. they eat well, filter is running, we have plenty of air the temperature stays about 72, the same as the other tank. they don't go on their sides just lay at the bottom.