Not jellyfish, belonging to invertebrates, but a relatively low-level marine organism. Although fish live in the same environment as jellyfish, jellyfish do not belong to fish because fish belong to vertebrates. The biggest difference between the two is the spine. Jellyfish have no spine, while fish have spine. In addition, fish have some outstanding characteristics that jellyfish do not have, such as breathing with gills, swimming with fins, breeding with eggs and so on. 1、 Are jellyfish fish? Jellyfish live in the ocean and are marine creatures. There are many other animals living in the ocean, such as fish. Therefore, many people mistakenly believe that jellyfish are also fish. In fact, this is a very wrong view. There is a great difference between jellyfish and fish. They are completely different creatures. Fish belongs to vertebrates and is an ancient vertebrate. Jellyfish are different. They are invertebrates and belong to a relatively low class of coelenterates. In contrast, the body structure of fish is more complex, while that of jellyfish is relatively simple. 2、 Why jellyfish are not fish has been introduced above. Jellyfish are invertebrates and fish are vertebrates. They are completely different creatures. Jellyfish are not fish. Some characteristics of fish are more prominent. For example, the way of breathing, fish breathe with gills. Jellyfish have no gills or respiratory organs. Their breathing mode is relatively special. They can only breathe with the help of ectodermal cells. Another example is the way of swimming. Fish swim with fins, but jellyfish have no fins. They can only eject water with the help of the contraction of the inner cavity. Another example is the way of reproduction. Fish generally reproduce by laying eggs, but jellyfish do not reproduce in this way.
It can be seen that the outstanding characteristics of fish are not possessed by jellyfish. It can be seen that jellyfish do not belong to fish. In fact, the invertebrates belonging to jellyfish are relatively low-level organisms, which are much lower than fish. （ShuiMuShiYuLeiMa，WeiShenMeBuShiYuLei）