1, different species: Hemiptera and croaker are two different fish species. Hemibarbus is a kind of fish that lives in fresh water or brackish water, such as Hemibarbus nigricans and Hemibarbus japonicus. However, croaker refers to marine life with toxic components, mainly referring to some sea snakes with poisonous glands and fangs, such as some species in the family Serpentidae.

2. The living environment is different: the fish mainly lives in fresh water or brackish water, such as rivers, lakes and estuaries. They live in crevices and water grass near the bottom of the water. The squid mainly lives in the ocean, inhabiting coral reefs, underwater caves and other sea environments.

3. Different characteristics and uses: The fish has a typical perch-shaped posture, with a flat and long body and a slightly inclined mouth. They feed on small invertebrates and are also some fishery and ornamental fish. However, salmon is toxic, and its poison glands and fangs contain neurotoxins, which pose a certain threat to human beings and other animals. The salmon is not used for food or other practical purposes, but is concerned because of its toxicity.