The lionfish, a vibrantly colored spiny and venomous predator from the western Pacific, is rapidly spreading in the Caribbean's warm waters, according to marine biologists who are studying the phenomenon.

SAN JUAN, Puerto Rico — A maroon-striped marauder with venomous spikes is rapidly multiplying in the Caribbean's warm waters, swallowing native species, stinging divers and generally wreaking havoc on an ecologically delicate region.

The red lionfish, a tropical native of the Indian and Pacific oceans that probably escaped from a Florida fish tank, is showing up everywhere — from the coasts of Cuba and Hispaniola to Little Cayman's pristine Bloody Bay Wall, one of the region's prime destinations for divers.

Wherever it appears, the adaptable predator corners fish and crustaceans up to half its size with its billowy fins and sucks them down in one violent gulp.

Research teams observed one lionfish eating 20 small fish in less than 30 minutes.

"This may very well become the most devastating marine invasion in history," said Mark Hixon, an Oregon State University marine ecology expert who compared lionfish to a plague of locusts. "There is probably no way to stop the invasion completely."

A white creature with maroon stripes, the red lionfish has the face of an alien and the ribbony look of something that survived a paper shredder — with poisonous spikes along its spine to ward off enemies.

The invasion is similar to that of other aquarium escapees such as walking catfish and caulerpa, a fast-growing form of algae known as "killer seaweed" for its ability to crowd out native plants. The catfish are now common in South Florida, where they threaten smaller fish in wetlands and fish farms.