Drifting against the brilliant blue backdrop of tropical, crystalline waters, the lionfish is exotic and beautiful. Its fine fins and thin, venomous spines feather out from its body, plump and painted in vertical stripes of white and rust red.

It's mesmerizing, lumbering there, until it opens its mouth.

Like a vacuum cleaner, the lionfish moves along the ocean floor, slurping up in gluttonous amounts of bait fish crucial to the ecological equilibrium of the already fragile coral reefs. In weeks, the lionfish can decimate the juvenile fish populations on a reef by 90 percent. It breeds at rapidly. It has no predators.

And it shouldn't even be there.

Native to Indo-Pacific waters, the lionfish, thanks to evolution, is hardly disruptive at home. But when fish hobbyists in Florida introduced the species to Atlantic waters in the 1980s, other sea creatures there did not know to see the invasive lionfish as a dangerous predator. In the three decades since, the species has overwhelmed the entire east coast of the U.S., spreading as far north as Rhode Island and south to the Florida Keys. They've bled into the Gulf of Mexico, throughout the Caribbean Islands and the northern coasts of South America.

They've even wandered out to Bermuda.

It was there, during a scuba diving trip last year, when Colin Angle and Erika Ebbel Angle were urged by locals to help fix the problem. She is a biochemist and the executive director of Science for Scientists. He is the CEO of iRobot, the company that built the Roomba. They both graduated from M.I.T.

During a break between dives, the ludicrous-sounding idea bubbled up.

In the 21st century, an era of drones and Teslas, they wondered if conservationists were thinking too primitively? Perhaps, the divers thought, what the effort needed was not additional spears, but something more advanced.

They decided on killer robots.

A lionfish caught in the waters off Biscayne National Park south of Miami. (Angel Valentin / The New York Times file)
A lionfish caught in the waters off Biscayne National Park south of Miami. (Angel Valentin / The New York Times file)

Within a year, the Angles established a nonprofit called Robots in Service of the Environment (RISE), tapped John Rizzi, another MIT graduate and aeronautical engineer, to lead the organization as executive director and commissioned the production of their stealthy invention.

They have no idea if it will work. But so far, nothing has.

"Nothing is truly impacting the invasive population today," Rizzi told The Washington Post.

Whole Foods grocery stores in Florida, the state called the "epicenter" of the problem, started carrying the fish, hoping it would encourage fishermen to kill more. Lionfish spearing tournaments are being held across the state. Fishing season for the species is never closed, reported the Tampa Bay Times, and officials enforce no bag limits. The Florida Fish and Wildlife Conservation Commission offered a bounty to any diver who speared 10 lionfish during lobster hunting season.

The creature, swimming inside a large aquarium, even made an appearance on Mark Cuban's reality TV show, Shark Tank, when two entrepreneurs with Traditional Fisheries tried to get investors to finance making lionfish meat a commercial product. The challenge, the men explained, is harvesting the fish. They live in deep caves and won't respond to baited hooks. Spearing them is the only way, requiring a great deal of manpower, and that's just the lionfish that live where divers can reach them. Some flourish much deeper, where humans can't swim.

The killer robot, Rizzi hopes, will get around those challenges.

A lionfish. (Erik Olsen / The New York Times file)
A lionfish. (Erik Olsen / The New York Times file)

The mechanism will use technology iRobot developed for the Roomba, powering the remotely-operated-vehicle (ROV) to move along the ocean floor. It will be controlled, "almost like a video game," Rizzi said, by a human on a boat above the surface, who will use an underwater camera attached to the robot to hunt down the lionfish. Attached to the ROV will be a retention bucket for the creatures and a tube to suction them once they've been killed.

The killing, Rizzi said, will be accomplished through electrocution.

Two probes, like metal sheets, box in the fish, then send an electric current through it, as if there were a wire there, Rizzi explained. Because the lionfish is an apex predator, at the top of the food chain, it fears nothing.

"What is really surprising to us … is that when you approach the fish they don't move," Rizzi said. "They don't swim away."

The goal is for these robot harvesters to fall in the hands of fishermen and ecotourists who will make lionfish hunting a sport. It should, Rizzi said, exceed the limitations currently inhibiting spear fishermen because the robot can navigate deep caves and ocean pockets unreachable by divers.

It might create jobs, Rizzi said, and expand the demand for lionfish commercially.

They hope to have the first fully assembled robot in the water by the end of the year, and the first commercial release by the beginning of next summer. At first, the devices will be expensive, Rizzi said, and require trained operators. But eventually, RISE is planning for widespread distribution.

"It has to be effective," Rizzi said, "but also safe, easy to use, and cost effective."

And despite their effort to seek and destroy the lionfish, Rizzi said RISE has received little pushback from animal rights and environmental groups. This effort, he said, is intended to be eco-friendly.

"We're kind of greener than the average fisherman," he said, "because we're going after the bad guys."

"It's much bigger than just killing fish."