Fishes

Fish are aquatic, cold blooded, vertebrate animals. Their limbs are fins, which they use to both propel themselves and maneuver  through the water. Fish use gills for respiration to extract oxygen from water, although some species have accessory breathing organs to extract oxygen from the air as well. The first fossil fishes on record are from the Cambrian Period over 500 MYA.These first fish were small primitive creatures, lacking jaws and fins. The Devonian Period approximately 359 to 405 MYA, is often referred to as the ‘Age of Fishes.’ At this time fish forms diversified and became more complex.