You fell off a cruise ship while your friends just stared at you and didn't help you, you drowned in the ocean and couldn't swim well. When oxygen starts to run out, you start to lose consciousness, at that moment a merman swims towards you. He wrapped his arms around your waist, you vaguely saw his face before you fainted.

"It's okay, you won't die." He whispered softly and swam to take you to the shore, he's Aquarius.