Aquatic invertebrates are the focus of extensive scientific research and conservation efforts due to their incredible diversity and ecological importance. They contribute to ecosystem functioning and provide valuable insights into evolutionary processes and adaptation. There are currently over 40 recognized phyla of invertebrates (not including the protozoans); many of these phyla are little known to veterinary medicine because they contain few species, have microscopic representatives, or possess no obvious economic value. In this talk the importance of aquatic invertebrate welfare will be discussed through the lens of analgesia, anesthesia, and euthanasia. The current evidence-based, state of the science will be reviewed for these important topics. There will be an emphasis on the most economically and conservation important taxa (coelenterates, mollusks, crustaceans, and horseshoe crabs).