what is the fish under my name in F.E.K

The community team lost to the FEK team in the Fizz Invasion event, so the Fizz icon is showing up for all FEK users. Don't worry though! It'll be back to normal by Monday.

http://boards.na.leagueoflegends.com/en/c/GD/4doOZARj-fek-event-fizz-invasion-2-urfs-unlikely-allies