SAN DIEGO — An unusual deep-sea fish made a rare appearance on the shore in San Diego this week.

The animal, a 4-foot lancetfish, was found dead on the sand at La Jolla Shores Wednesday afternoon, according to the Scripps Institution of Oceanography at UC San Diego, which collected the fish to be preserved and analyzed.

Scripps oceanographers said it was only the 17th lancetfish to be found on a San Diego beach since 1947, and the third from La Jolla Shores. The last one was found in 1996.

Lancetfish sport fanged jaws and large eyes, with a sailfin and long, slithery body that can grow up to 7 feet, according to the National Oceanic and Atmospheric Administration. As “ambush predators,” the fish float quietly until unsuspecting prey get close enough for them to pounce, the NOAA says. They feed on various fish and invertebrates but are also “notorious cannibals,” devouring fellow lancetfish.

The fish live offshore in the deep ocean but “vertically migrate” and can be found from the surface to depths of 6,000 feet, Scripps scientists explained.

The institute’s Ben Frable, who is in charge of marine vertebrate collections, worked with lifeguards to collect the one that washed up in La Jolla this week.

“Some important info for the public: If a person finds an unusual organism like this, do not take it home,” a Scripps spokesperson said by email. “Much of La Jolla is a Marine Protected Area (MPA) and taking home organisms is prohibited.”

Instead, beachgoers should let lifeguards know or contact Scripps at 858-534-3624 if they spot something unusual, the institute said.