* Size and Aggression: Tiger sharks are massive predators that can grow up to 14 feet long. Molly fish are small, peaceful fish. A tiger shark would see a molly fish as a snack and quickly devour it.
* Habitat: Tiger sharks are marine animals, typically found in warm coastal waters. Molly fish are freshwater fish, usually kept in home aquariums. Their environments are completely different.
It's important to remember: Never attempt to keep animals together if they have drastically different needs and could pose a threat to one another.