Lionfish, or Pterois, are a deadly type of fish that live around reefs, although they are native to the Indo-Pacific region. These fish have been known to be invasive, and with no natural predators, can easily destroy a new environment. Adult lionfish have also been known to be hostile towards divers. Their stingers can cause many painful symptoms, along with swelling and tingling sensations. The fish shown here is probably 1 inch, and will grow to about a foot.