( 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 . '' Giant eyeball washes up on beach . After a 15-minute swim dragging the 400-pound carcass , she needed help from 14 others to lift the fish out of the water at Toyon Bay , California . `` I was really amazed . It was like seeing something in a dream , '' said Mark Waddington , the senior captain of CIMI 's sailing school vessel the `` Tole Mour '' who gave Santana a hand . `` It 's the first time I ever witnessed an oarfish this big . '' Discovery makes a splash : The rarest whale . `` Oarfish 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 . `` It is believed that oarfish dive over 3,000 feet deep , which leaves them largely unstudied , and little is known about their behavior or population . '' Waddington , who has been with CIMI since 1994 , said it remains unclear why the oarfish was found in shallow water this time , but it appeared to have died naturally . Waddington said while the oarfish 's carcass is still being preserved in ice , CIMI has been sending some of its tissues and other samples to marine scientists , including Dr. Milton Love , a fish expert from University of California at Santa Barbara , to study its DNA and diet habits . Waddington said CIMI will likely to keep the fish 's skeleton for educational purposes . Its program attracts more than 30,000 school-age children each year . Seal gives shark the slip in great white photo . Face to face with great white sharks to sold '450-million-year mystery ' Shark found on New York subway car .
Marine science instructor discovered the 18-foot oarfish while snorkeling . Oarfish usually live in the deep sea , marine scientists say . It is unclear why the oarfish was discovered in shallow water . The discovery could lead to finding out more about the fish .