A climbing perch is an olive green freshwater fish native to Papua New Guinea. It's only about 10 inches long, but according to Nathan Waltham, a researcher at James Cook University in Queensland, Australia, the climbing perch is tiny, but tough.
The fish has spiky gills on both sides of its head. "It can extend that out and it can lock those into place. And along the edge of those gill plates are sharp spines," Waltham said, according to PRI via MSN. "They can flex out those gill plates on the side of the head, which means they can actually - with the sharps spines - leverage themselves across land."
"So if you can visualize a water hole that's drying up, conditions becoming unfavorable - and this fish can detect that and decide then to move out of that water," Waltham explained. "So by using those sharp spines [it can] drag itself out, move across land and find a new water hole to take up refuge."
The climbing perch can even breathe air and live out of water for up to six days, Waltham said, according to PRI. Scientists are monitoring the fish and believe it has adapted to survive in saltwater, according to the Telegraph. And those spikes aren't just for strutting to a new watering hole.
"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," Waltham said. "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."
The issue is that the aggressive perch didn't stay in Papua New Guinea. It most likely hitched a ride on a fishing boat and arrived at some nearby Australian islands. Waltham is working with locals to find and eradicate the climbing perch before it can invade and disrupt Australian habitats.