(CNN) -- A marine science instructor's late-afternoon snorkel off the Southern California coast last Sunday was first met with shock and soon excitement when she discovered a gigantic oarfish, a deep-sea creature that remains little known to the science world and people outside. Jasmine Santana was about 15 feet underwater when she found the 18-foot-long, silvery fish with reddish fins and eyes the size of a half-dollar staring at her from the sandy bottom. Realizing it was dead, she snatched the fish's tail, and using buoyancy and low tides, powered her way back on shore. "I was first a little scared," said the still-thrilled Santana, who has been working for Catalina Island Marine Institute since January. "But when I realized it was an oarfish, I knew it was harmless."
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Marine science instructor discovered the 18-foot oarfish while snorkeling
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Oarfish usually live in the deep sea, marine scientists say
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It is unclear why the oarfish was discovered in shallow water
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The discovery could lead to finding out more about the fish
"@placeholder are found in all temperate to tropical waters, but are rarely seen, dead or alive," CIMI, a non-profit marine science education group, said in a release.