They have survived for 400 million years and have been dubbed "living fossils". But a leading scientist has warned that the coelacanth may succumb to extinction because of human interference unless action is taken.
Hans Fricke, a marine biologist at the Max Planck Institute in Seewiesen, Germany, is an authority on the species and was the first person to photograph the fish in its natural environment.
Until 1938, the coelacanth was thought to have been a long-extinct contemporary of the dinosaurs. Then a live specimen was caught by fishermen off the coast of South Africa.
But in an article in the Journal of Fish Biology , Dr Fricke says that its survival is in jeopardy. He says that the principle threat comes from the fishermen of the Comoros, the Indian Ocean island state in whose coastal waters the coelacanth lives.
They use long lines that reach depths of up to 700m from their outrigger canoes while hunting for other quarry and occasionally pull up the fish.
Coelacanth flesh is inedible but the accidental toll is having an impact on the small population, estimated to number just a few hundred.
Dr Fricke says that foreign aid has enabled the fishermen to buy outboard motors, meaning they could take their boats further offshore and away from the inshore haunts of the coelacanths. But in recent years there has been no money to ensure the upkeep and replacement of the engines and so the fishermen have returned to their traditional inshore fishing grounds.
More help is needed to preserve the species, he warns.
"The coelacanth has become a kind of icon for evolutionary longevity," Dr Fricke says. "Hardly another vertebrate species can match its claim to have survived five major crises of extinction during geological history. It is hoped that they will survive the sixth crisis of extinction, the manmade one."