These fish, which belong to the class Percopsiformes, generally live in fresh water in North America. Some evolutionists claim that fish belonging to this class possess primitive features. However, investigations have revealed that the vertebrates in question actually have very complex structures. Some families even amaze evolutionists through the extraordinary features they display in nest-building and caring for their offspring. The fossil pictured here is around 50 million years old and shows that fish of this species have survived exactly the same over the last 50 million years.