"Caribbean Prawns" joke

Far away in the tropical waters of the Caribbean, two prawns were swimming around in the sea - one called Justin and the other called Christian. The prawns were constantly being harassed and threatened by sharks that patrolled the area.
Finally one day Justin said to Christian, "I'm bored and frustrated at being a prawn, I wish I was a shark, then I wouldn't have any worries about being eaten..."
As Justin had his mind firmly on becoming a predator, a mysterious cod appears and says, "Your wish is granted," and lo and behold, Justin turned into a shark.
Horrified, Christian immediately swam away, afraid of being eaten by his old mate.
Time went on and Justin found himself becoming bored and lonely as a shark. All his old mates simply swam away whenever he came close to them. Justin didn't realise that his new menacing appearance was the cause of his sad plight.
While out swimming alone one day he sees the mysterious cod again and can't believe his luck. Justin figured that the fish could change him back into a prawn. He begs the cod to change him back so, lo and behold, he is turned back into a prawn.
With tears of joy in his tiny little eyes, Justin swam back to his friends and bought them all a cocktail. Looking around the gathering at the reef, he searched for his old pal.
"Where's Christian?" he asked.
"He's at home, distraught that his best friend changed sides to the enemy and became a shark," came the reply.
Eager to put things right again and end the mutual pain and torture, he set off to Christian's house. As he opened the coral gate the memories came flooding back. He banged on the door and shouted, "It's me, Justin, your old friend, come out and see me again."
Christian replied "No way man, you'll eat me. You're a shark, the enemy and I'll not be tricked."
Justin cried back "No, I'm not. That was the old me. I've changed."
"I've found Cod. I'm a prawn again, Christian!"