What anesthetic is most commonly used for aquatic animals, including amphibians?

MS-222, or tricaine methanesulfonate, is the anesthetic most commonly used for aquatic animals, including amphibians, due to its effectiveness and safety profile in these species. It is a water-soluble anesthetic that is readily absorbed through the gills of fish and the skin of amphibians, allowing for rapid induction of anesthesia.

MS-222 is particularly favorable because it can also be used in an aqueous solution, which is essential in aquatic environments. Additionally, it provides a reversible anesthetic effect, allowing for recovery of the animal after the procedure is completed.

In contrast, although the other anesthetics listed have specific uses in veterinary medicine, they are not as widely applicable or effective in aquatic species. Ketamine is primarily used for terrestrial mammals and may require higher doses in aquatic animals. Isoflurane is a volatile anesthetic used primarily in inhalation anesthesia, which is not practical in an aquatic setting. Propofol is another injectable anesthetic that is primarily utilized for short procedures in terrestrial animals and does not have the same suitability or ease of use in aquatic or amphibian species as MS-222 does.