Fish hole up in trees, according to reports in Daily Mail 17 Oct 2007 and New Scientist, 19 Oct 2007, p20. Killifish are small fish, about 2 inches (5cm) long, that live in muddy pools in the mangrove swamps around the Caribbean Sea. The muddy pools often dry up, but the fish are able to survive for months at a time by taking to the trees. The fish hole up in rotting logs by crowding into tracks made by insects, where they lie lined up “like peas in a pod”. In order to survive for long periods out of water, the fish change their gills so that they retain water and nutrients and add proteins to their skin to enable them to excrete waste products.

Daily Mail

Editorial Comment: These fish live in an environment that is very changeable, but they can survive when the swamp dries up because they already have the built in ability to change their gills and make the extra skin proteins. This extreme example of adaptation shows that adaptation is a real biological process, but it has nothing to do with evolution. Adaptation is the ability to cope with changes in the environment, and can only occur if a living creature already has the means of doing it. Obviously any fish without this ability does not get a second chance to evolve it when the pond dries out. (Ref. ichthyology, environment)

Evidence News 28 Nov 2007