The first time you get tiger shark you need to win the game. Then, go to campbell castle and it will say "New Mission Unlocked The Last Of The Tigershark s." A video will play and jazmine will tell you she is from a city called bangelo and there is a legend there about ademcoshedhmudchli (tigersharks) and that they became extinct long ago. She'll then say "Or So We Thought." She'll say some club boss in India has found one. She'll then tell you you can win it if you beat him. Go to mumbai and fight Sanjay. You may notice the skull in front of his name has dissapeared. He will have a tigershark pup level 1. I recomend a Flameclaw with maxed attack as the tigershark dodges quick and strong attacks. When you beat him you get the tigershark.
The second time, you go to mumbai again. There will be a new member, Nomad. Fight him. He cycles between tigershark and zaphyra, so don't worry if its not a tigershark. It could be a mutant or a regular. After you beat him, you get the tigershark. In mutant, tigershark regenerates stamina faster than normal.