Hi Laura, it sounds to me as if your fish has something called
'Swimbladder' which affects it's ability to swim properly. I have 2
fan tailed goldfish and they have suffered with this as well.
Sometimes it also has the opposite affect that the fish sinks to the
bottom of the tank. You can get treat it with something from your pet
store/fish eqatic called Swim bladder treatment which you have to add
to the water. This is a serious condition so get it sorted out before
it's too late. I hope that helps

Laura wrote:
My lionhead goldfish stays at the top of the tank 24-7, has for 2
months, except for when he eats, and he eats good but soon as he's thru,
he heads for the same exact spot and just "hovers" there. He honestly
stays in about a 6 sq. inch space, on occassion he'll swim in a circle.
Should I be concerned? No visible problems either and no gasping. I've
had him a year. All water conditions are good.