The best example of long-lived fossil forms may be the stromatolites, which have survived apparently unchanged for 3.5 billion years. However, cyanobacteria/stromatolites have shown an ability to adapt to harsh conditions, such as hot water springs in Yellowstone. Another test is with highly developed animals, since they tend to go extinct and be replaced by other species when conditions change substantially. An outstanding example is the coelacanthe (see-la-kanth), a fish that appears in fossil form in the Devonian era, 400 million years ago. In 1936, a coelacanthe apparently identical to the fossil ones was caught off South Africa, and since then they have been found living in the waters of Indonesia also. Below is a comparison of an ancient fossil (below) with a recently caught specimen (above).