Scientists have made a big discovery on a tiny fish in Thailand that could help them understand how land creatures evolved from the sea.

The walking cavefish, which can walk on land and climb waterfalls using tiny limbs like an amphibian, could unlock the secrets of evolution for researchers, according to a New Jersey Institute of Technology statement.

The fish, whose scientific name is Cryptotora thamicola, is blind and just two inches long, and is found in caves in northern Thailand. It’s a fish that isn’t found anywhere else on Earth, and has features completely unlike any other.

The fish is capable of climbing rough and smooth wet surfaces alike out of the water using a pelvis and vertebral column to support its weight.

The finding has major implications for how animals transitioned from finned to limbed appendages about 420 million years ago.

“It possesses morphological features that have previously only been attributed to tetrapods. The pelvis and vertebral column of this fish allow it to support its body weight against gravity and provide large sites for muscle attachment for walking.”  Brooke Flammang, an assistant professor in the NJIT Department of Biological Sciences, said in a statement. “This research gives us insight into the plasticity of the fish body plan and the convergent morphological features that were seen in the evolution of tetrapods.”

The findings were published in the journal Nature Scientific.