National Geographic News


Photograph by Thomas Redd, My Shot

The colorful lionfish presents an attractive appearance, but its arsenal of needlelike dorsal fins is actually meant to warn others away. Too-curious humans can receive a quite painful and potentially dangerous sting from these spines. Lionfish hail from Indo-Pacific reefs but they have recently spread to other warm waters, like the Caribbean, where they are causing some ecological concern by thriving as an invasive species.