The ocean is a deeper hue of blue off the coast of Florida. About 30 meters (100 feet) down, the water is clear. The colors of the reef are brilliant. Near a blazing orange barrel sponge is a group of fish. They seem to hang, motionlessly, in the water. They look like a herd of lazy zebras, only their stripes are reddish‑brown and white.

Around their mouths and above their eyes are fleshy knobs. Jutting from their backs and fins are deadly spines. They look menacing and beautiful at the same time.

A short distance away, a diver appears. He aims the barbed end of a speargun at the head of the nearest fish. He pulls the trigger and strikes the fish. None of the other fish move. It’s as if they hadn’t noticed what just happened. The diver shoves the dead fish into a pouch and takes aim again.


A Fish Out
of Its Waters

Why would a diver kill a lionfish? Divers take on this task because lionfish are not a natural part of the environment here. They don’t belong off the coasts of the Atlantic Ocean and in the Caribbean Sea. Instead, they are an invasive species. Their presence here hurts local fish populations. It’s also a serious threat to the reef itself.

Lionfish are native to the South Pacific and Indian oceans. There, they live in balance with other living things. Lionfish populations are kept in check by birds and fish that eat their eggs as well as larger predators that eat them. But in the Atlantic Ocean, they have no natural predators. There is nothing to keep the lionfish population in check.

Getting a Fin‑hold did these lionfish get in the Atlantic Ocean in the first place? Good question! It's a bit of a mystery.

There are some interesting theories. They arrived here trapped in the ballast tank of Pacific cargo ships. A breeding pair escaped from an aquarium during Hurricane Andrew. A hotel mishandled the filtration system on its lobby aquarium and accidentally pumped lionfish out to sea.

Probably none of these are true. It’s likely that too many tropical fish owners on the southeast coast of Florida decided to put their pets out to sea once the lionfish got too big for their aquariums.

The first verified report of lionfish in the Atlantic Ocean was in 1985, when a few were detected off the coast of Dania Beach in Florida. Genetic analysis shows that every single lionfish in the Atlantic Ocean came from fewer than 10 original females. Since 2000, the population has exploded. That’s a big problem.