The Lionfish has very long pectoral and dorsal fins. The body is covered with red to black bands on a pale background. Adults often have white spots along the lateral line. A tentacle is usually present above both eyes. The tentacle is variable in size and shape, usually long in juveniles and leaf-like in adults. The fish grows to 38 cm in length. It has extremely venomous fin spines, including all 13 dorsal fin spines, 1 pelvic fin spine and 3 anal fin spines. When disturbed by a diver, it often makes little effort to swim away. Instead it points its dorsal fin spines towards the intruder. It is a tropical species found widely throughout the Indo-Pacific.