When your phone's personal banner reads IVI on a fish backround...
When you have an MFK t-shirt even if it means drawing fish on it with a sharpie...
If you made an Aquarium by drawing individual fish on index cards and stuffing them in your pockets during Social Studies...
If you have a fish keeping video game...
if you know the spanish name for Black pacu (Tambaqui)
You know you are an MFKer :
when you worry your landlord will start charging you for the water (included, for now)
feeding time resembles something from the zoo
you have more poisonous fish flesh (still living) than a Japanese sushi bar.