For an interesting study gather a few books discussing the drift of tectonic plates since the time of Pangea. And then do some reading on the classification, history, and distribution of one family of fresh water fishes, Cichlidae.
Today cichlids appear on every continent except Australia. They are very intolerant of salt, or even brackish water, so they did not migrate from continent to continent, nor even from river to river via ocean, and certainly not over land. Anyway, not until man started packing all kinds of different species all over the world via air and ocean freight.
Consider how the continent of Australia separated from Pangea before the rise of Mammalia, and marsupials became the dominant animals of Australia, while they were displaced by mammals everywhere else.
Every discovery made in the field of geology enhances the evidence for evolution.
Fish end up in lotsa places they got no business being.
You have the faith that a fish that ain't where you think it should be, proves the theory of evolution.
