Fish Euthanasia

From Microcosm Aquarium Explorer

The long-accepted standard of euthanasia for fishes and other aquarium livestock is freezing in water.

Today, there is some debate about how humane this is, and there are experts who now advocate the use of an anaesthetic overdose to dispatch a sick or unwanted specimen.

One of the most effective anaesthetics for fishes is the inexpensive and readily available clove oil.

Recent scientific reports have given clove oil higher ratings than MS-222, the previous gold standard for anaesthetizing or euthanizing a fish.

Clove oil (eugenol) is available at health food stores. It is not readily soluble in water, so it needs to be emulsified by blending in water or shaking vigorously in a sealed plastic bag of water. Alternately, it can be added to a quantity of ethanol (vodka will do) and shaken before adding to a treatment aquarium or bucket.

The fish can be put to sleep very quickly and painlessly, after which it should be wrapped in paper and plastic and frozen overnight or for a period of hours before being buried or properly discarded with household trash. (Alternately, the fish can be left in the clove oil-treated water until death occurs, making freezing unnecessary.)

For large fish, biologists recommend quickly severing the spine just behind the head. Snakeheads, for example, can survive for days out of water and are regarded as difficult to kill, short of using a knife or potent poisons.