Anesthetic and sedation monitoring and resuscitation are similar to those for other vertebrates.Euthanasia is most commonly performed using an overdose of an immersion drug but injectable agents are also effective.It will be more stressful for the fish without sedation.Place a heavy towel dampened with cold tap water as your base and then place another heavy cold tap water dampened towel over the fish covering the head but leaving the areas you're working on exposed.
The clove oil should be mixed with a little warm water first before adding it to the water and fish slowly.
Oil of cloves can be used as a replacement for the commercial treatments and it can be used to sedate, anaesthetise and euthanise when the dosage is altered appropriately.
The disadvantage when using oil of cloves rather than a purpose made product is that oil of cloves is: The first of these problems is easily overcome by dissolving the required dose of oil of cloves in a small volume of warm water by vigorous shaking before adding it to the fishes water.
Analgesia is an area in need of significant research as only a few studies exist and they provide some contrasting results.
However, fish have mu and kappa opiate receptors throughout the brain, making it reasonable to expect some effect of at least opioid treatments in fish experiencing noxious stimuli.