Cephalaspis ("Head Shield") was a genus of armored goldfish-sized to trout-sized detritivorous fish that lived in freshwater streams and estuaries of Early Devonian Western Europe. It is a member of the Osteostraci, one of many groups of Palaeozoic armored jawless fish. This animal was thought to have been a feeder of the ocean floor. What it found was mini microscopic animals.