Movement across land requires significant evolutionary changes compared to movement through a liquid medium. Or so biologists thought. Alice Gibb of Northern Arizona University and her colleagues from that school, Wake Forest Universtiy and Vassar College have found that some fully aquatic fish can move across terrestrial environments quite successfully with no obvious modifications of body plan at all. In fact, they use some of the same strategies to escape predators on land as they do in the water.
For their studies, the researchers used killifishes, a group of teleost fish similar to guppies, that tend to live at the water’s edge. Killifishes often find themselves temporarily stranded on land, either intentionally or by accident. Once there, they employ the same technique that gives them a fast start escape in the water, namely a tail flip. In the water, a rapid snap of the tail gives the fish a burst of speed whereas on land it causes the fish to spring several body lengths away.
The significance of this finding is that it suggests that many more types of aquatic organisms may have made forays onto the land than previously thought.
You can see some video clips of the leaping fish here. No fish were harmed during the making of these videos.