Assistant Laboratory Animal Technician (ALAT) Practice Exam

What commonly used anesthetic and euthanasia agent for amphibians and fish is administered in water?

1. Acepromazine

2. MS-222

3. Ketamine

4. Isoflurane

The correct answer is: MS-222

MS-222, also known as tricaine methanesulfonate, is a commonly used anesthetic and euthanasia agent specifically for amphibians and fish. It is effective because it can be dissolved in water, allowing for a simple and efficient method of administration. When MS-222 is added to water, it is absorbed through the gills in fish or the skin in amphibians, facilitating anesthesia or humane euthanasia. This mode of administration is particularly beneficial in aquatic species, as it minimizes additional stress or harm that might occur with injection methods. The other agents listed, while they serve important roles in anesthesia for other species, are not typically administered in water or are less effective in this context. For instance, acepromazine is primarily used for sedating dogs and cats and does not have the same applications in aquatic environments. Ketamine is often used in mammals and requires injection for efficacy, and isoflurane, while a vaporized anesthetic for gas anesthesia in various species, is not suitable for administration in water for amphibians and fish. This specificity makes MS-222 the correct choice in this context.