A broken heart coma is a state of unconsciousness, in which a person is in a deep sleep with his/her heart broken and fails to awaken until another person gives that person a cure for it called the "Kiss of True Love".
The causes of a broken-heart coma are:
- The breaking of a person's heart
- When a secret is kept from that person
- Hyperventilating in a bag so much it can cause a start of damage
These causes were made by Oscar in the episode Oscar's Secret Admirer, in which Oscar learns that Milo has made up a fake love letter and put it in his locker. The neurotic fish hyperventitates into a bag, feels his heart break, and falls into the coma. Milo catches him, and Dr. Frog arrives on the scene. He explains to Milo that Oscar's got a doozy of the broken-heart coma, and the only cure for it was the ultimate one: the Kiss of True Love. Girls such as Finberley, Koi, Clamantha, and Shellsea all kiss him, but Oscar still does not stir even a little. Right when Bea was prepared to do the same, however, Milo pushes her out of the way. While crying tears of sadness and guilt, he says a confession of his mistakes to Oscar (not realizing that all Oscar wanted was just "one true love"). With that, he kisses Oscar, and cries on his body, and Oscar is at last revived.