The crazy cool thing about snorkeling in Hawaii is that about 25 percent of the fish you can see out here are endemic to the islands. You won’t see them anywhere else! There are very few places in the world where you can find a comparable number of unique fish species. Why is that? The Hawaiian Islands (which are actually the tops of an underwater mountain range) are separated from all other underwater mountain ranges by a distance of more than 1,000 miles, far greater than the distances between any other Pacific islands and their neighbors. This massive distance between Hawaii and other island chains is what paved the way for the emergence of many new species. Isolation encourages endemism because the fish populations are much smaller and more localized, and therefore are more easily affected by genetic changes. Two examples of endemic fishes are the Milletseed Butterflyfish and the Saddle Wrasse - they are super abundant down here, and a probable reason for that abundance is that they are the most perfectly adapted to the local ocean conditions, in comparison to non-endemic fish.