Hawaii’s environmental extremes (read a series of active volcanic islands isolated in the middle of the ocean) make it a hotbed of novel evolutionary adaptations. Take goby fish in the genus Sicyopterus, for example. These lowly little bottom-feeders spend their days sucking algae off the rocks of stream beds. But that same sucking mechanism also allows the fish to climb up waterfalls over 300 feet tall. The question is how these two activities are related.
This little goby fish saves its host coral by keeping toxic algae
When coral are threatened by encroaching toxic algae, they do not have the luxury of running from their enemy. That is not to say these stationary creatures are defenseless, though. Acropora coral has evolved to emit a chemical call for help, and within minutes, a goby fish will show up on the scene, ready to nibble off the algae. Researchers recently discovered this underwater partnership in the waters near Fiji. They say this symbiotic relationship is the first known example of a species chemically signaling another in order to remove a competitor species.