The fact of the matter is that the Wobbegong Shark, Whale Shark, Nurse Shark, and the Zebra Shark are some of the most harmless shark species on Earth. In Australia, they make fish and chips out of the Wobbegong! The Whale Shark isn't a whale, but it certainly acts and eats like one. The Nurse Shark swims slow as a slug and prefers chowing on shellfish and stingrays. And the Zebra Shark only grow to a maximum of 8 feet; they're also used to being doted on by underwater tourists. All this proves that Crowdstar did their research when they chose these sharks for the game.
That said, the Wobbegong and Zebra Shark are both 79 Pearls or 66 Facebook Credits ($6.60 USD). Whale Shark costs 60 Pearls or 50 FB Credits ($5 FB Credits), while the Nurse Shark goes for 68 Pearls or 57 FB Credits ($5.70 USD).