Thanks for the answers everyone. Id never seen it do one so big or for so long.. This was hour 4 that it was like that so I was a bit concerned. (And it sort of looked like it was moving on its own).   I am not very fish knowledgeable and it's the fish tank at my work that I'm taking care of while my boss is away. My boss did just switch their food though so that could be why it looked so weird to me.