Five days. According to the query of Health Care Network, the digestive system of shrimp is relatively simple, and the time for digesting food is relatively fast. After five days without eating, its digestive system has been emptied. Penaeus monodon is an arthropod belonging to Penaeidae, also known as Penaeus monodon, Penaeus monodon, Penaeus bambusae and Penaeus pentaphyllum.