That's one small step for a fish, one giant problem for Australia.
Australia has its fair share of imposing animals, but researchers say that a non-native fish that walks on land could pose a real threat to some of the continent's wildlife. The invader is called the climbing perch.
An expert on the species, Nathan Waltham of James Cook University in Queensland, Australia, told Public Radio International that a set of spiny protrusions on the 10-inch fish's gill plates help it "walk" across the ground. The fish spreads out the gill plates and uses the spines to pull itself along in search of water.
In action, the move looks more like a controlled flop. It's not the most elegant way of getting from one water hole to the next, but it's effective. And that's not the only feature in the creature's favor.
The fish has lungs in addition to gills, Waltham told the Guardian, so it can breathe in air as well as water and live on land for several days. It's also capable of surviving in either fresh or salt water.
All these adaptations give the climbing perch a competitive edge in wetland environments that could be bad news for native species. “When they populate an area they’re not commonly found in, they can disrupt the balance of that habitat,” Waltham told the Guardian.
The olive-green fish is native to southeast Asia and has propagated across Indonesia and Papua New Guinea over the last 40 years, according to the Guardian. Now, Waltham said, it's been found on the Torres Strait islands of Boigu and Saibai, the northernmost inhabited islands in Australia.
Waltham warned that the climbing perch would pose a "major disaster" for native species of Australian birds and fish, should it hit the mainland. The very same spines that help the perch negotiate dry land can prove lethal to predators.
"If a larger fish or a bird or some other animal tries to eat the climbing perch, it's natural defense is to flex and lock in place those gills," he told PRI. "And in doing that the climbing perch can get caught in the throat and unfortunately in doing that, the animal that's trying to eat the climbing perch is not going to survive."
Australia has a history of problems with invasive species, and we're not referring to Johnny Depp's dogs.
For instance, cane toads, which were introduced to Australia in 1935 in an effort to control beetles that ate sugar cane, quickly spread because of a lack of natural predators. To make matters worse, the toxins in the toads' skin poisoned native animals that tried to eat them.
Other animals, such as rabbits, were introduced to Australia by early settlers but soon became pests -- again, because they lacked natural predators.