Fish at my desk

So I bought some goldfish in efforts to decorate my desk at work.  I have come to notice that I think one of them has been having what I can only describe as a seizure.  He sits there for a moment then turns upside down starts to float then comes back to life and shakes around and swims in repeated circles… He is truly odd or had a disorder.

** UPDATE **
Attached is a picture of the fish per Jake’s request..

Fish at my Desk
Fish at my Desk

*** UPDATE ***
Looks like one of my cheap Walmart fish got Dropsy… now there is only one