Borris is a male blue butterfly fish and the first character to play with. He grows the fastest of all characters.
Goliath the Great White Shark:EditGoliath is a male Great White Shark and the last and 6th character ingame. He's the biggest character ingame and the first to fight the intruder.
The Mystery fish, Alien Intruder or Intruder isn't playable until you have truly deafeted him. Then you can use the Intruder profile to play as him all levels again.