Ex-prawn conversion therapy doesn't work

This is making the rounds on the internet this weekend:

One day two prawns were swimming around in the sea. One was called Justin and the other called Christian. The prawns were constantly being harassed and prawn-bashed by sharks.

Finally one day Justin said to Christian, "I'm fed up with being a prawn. I wish I was a shark, and then I wouldn't have any worries about being eaten."

A large mysterious cod appeared and said, "Your wish is granted." Lo and behold, Justin turned into a shark. Justin was overwhelmed with gratitude, and he begged the stranger to tell him his name. "Cod. Just one name, like Madonna and Cher", said the stranger, who then swam away.

Unfortunately, Christian was terrified by his friend's new appearance, and he also swam away, afraid of being eaten.

Time passed, and Justin found life as a shark boring and lonely. All his old friends swam away whenever he came close to them.

While swimming alone one day, he saw Cod again and he thought perhaps the mysterious fish could change him back into a prawn. He approached Cod and begged to be changed back; and lo and behold, he found himself turned back into a prawn.

Happy as a clam, Justin swam back to find his old friends. Arrivng at his old reef, he asked the closest fish, "Where's Christian?"

"He's at home, still distraught that his best friend changed sides and became a shark", came the reply.

Eager to put things right again and end their estrangement, he set off to Christian's abode. He banged on the door and shouted: "Christian, it's me, your old friend Justin. Come out and see me again."

Christian replied, "No way man, you'll eat me. You're a shark now, and I won't be tricked into being your dinner."

Justin cried back, "No, I'm not. I've changed. I've found Cod. I'm a prawn again, Christian."