Shrimp is a kind of crustacean that occurs in all oceans, freshwater lakes and streams. Shrimps range in length from a few millimetres to more than 20 centimetres (about 8 inches). They are an important source of food for humans. The body of the shrimp has two main parts – the abdomen and the cephalothorax (head and thorax fused together). The cephalothorax is covered with a carapace. The heart is located in the cephalothorax.