my fish is dancing

Question
my fish is seem liking dance he jumps and flips around when i come near him. and he hides behind the giant plant he has when i put my cats face over the tank!!

This is a goldfish (the one with the bubbly eyes)
he has a 10 gallon tank to himself lots of places to hide, he is 3 inches long, and 2 inches wide, the temature stays a room temp. (which is 78 degrees F) i have a pump that cleans the water and i check on the maintaince of the pump every week

Please tell me whats wrong with my fish, Dude, (thats hes name) thanks totally

Answer
Hi Harold:  Dude asked that you not put the cat anywhere near the tank... I'd hide too if I were 3 inches by 2 inches and saw a cats face  hanging above me.  Do you actually clean the tank? the gravel? do water changes?   It sounds to me like your fish is traumatized.  Scared fish lead to stress which kills fish... so do Dude a favor and do not scare him.  What do you feed him?  dave