Coelacanths are deep-sea fish that live off the coasts of southern Africa and Indonesia and can reach up to two meters in length. For a long time, scientists believed they were extinct. Coelacanths are deep-sea fish that live off the coasts of southern Africa and Indonesia and can reach up to two meters in length. For a long time, scientists believed they were extinct. Evolution Paleontology & Fossils Phys.org – latest science and technology news stories