Gold fish acting different!!!!

Question
I have 4 gold fish in a 30 gallon take. They have all been fine for the last few months. Since there move to the bigger tank they have been happy as can be. But, Recently the have all started to act different.. They are now all just hanging out on the bottom of the tank. They are hiding in the bottom near the fake plants.. Also, I have one fat goldfish who is not being really really weird. He/she is swimming like straight down almost all the time. Unless its feeding time.. I am just wondering what is going on? Its like they are sleeping all the time. These fish are very well taking care of. Any help would be great.

Thanks in advance
    Frank III

Answer
Did you cycle your new tank before you moved the fish? If not, then your water has become toxic to your fish and they are shutting down.  Have your water tested at your LFS for ammonia, nitrites and nitrates.  You will have to do 50% water changes every day until the levels start to drop and then 25% a day until all the levels are back to zero.