You were born under the Delphinus or Dolphin constellation, ever since you were young, your parents got you for your room giant fish tanks, books and movies about dolphins and all that other stuff, they even took you to aquariums to see dolphin shows. You wonder why you have to see these Cetaceans. In school they even give lectures about Dolphins, and you even get served Fish during Dinnertime at the table this all seems so strange to you.
One day you wake up finding it hard to breathe. It seems that you can no longer breathe air, but that isn't right. You still have lungs so Air should be breathable to you, but you find yourself suffocating, as you are gasping for air, your parents hear the commotion, and they pick you up and put you in the Giant Fish Tank. You are about to inhale the water, but that makes it almost impossible to breathe as well. You still have lungs so inhaling Water will only make you drown.
You try to surface out of the Giant Fish Tank, you do, and you find that you can breathe again. You try to get out but when you do you find that you can't breathe again. Finally, it hits you. You can only breathe air while your body is in the water, you have no choice but to stay in the Giant Fish tank.
Later you are taken to the marine institute, to conduct research on your changing physiological needs, they find it fascinating that you can't breathe air unless your body is in water they might have to run a few tests in the future to find out why that is.
Eventually you go to School and the other students are amazed that you spend all your time in the water.
Eventually the last bell rings and your Giant Fish Tank is moved from the school to your room in your house. You sleep on top of the water.