Hawaiian fish counts rock-climbing as one of its hobbies

When the Hawaiian fish, the stream goby, migrates upstream to breed, it must climb up the islands many waterfalls, which can sometimes be hundreds of feet tall. Amazingly, the tiny fish inch up the waterfalls, against streaming water, by gripping the rocks with their mouths and a sucker located on the bottom of their stomachs.

Even better, the steep climb isn't considered the most difficult part of the fish's migration. Before they climb, they must pass through areas of water filled predators who would love to have the goby for a mid-morning snack.

I learned about the stream goby from this article in Science News.