Livestock Euthanasia – A Taboo Subject?

Q) I have never been sure of the best way to dispatch ailing livestock. There seem to be many differing opinions on the subject. Which techniques are best?
David Wallace, Surrey, United Kingdom.

A) The whole subject of livestock euthanasia has always been a sensitive one, creating very little regular and open discussion but nevertheless generating a great deal of strong feeling and disagreement whenever the topic is broached.

It is an unfortunate fact of life that all living organisms must eventually die; fish and invertebrates are no exceptions. As hobbyists, we occasionally, and sadly, have to hasten that demise to avoid unnecessary suffering. Unpleasant as the task might be, all aquarists should be aware of how they can dispatch a fish or invertebrate in a humane fashion if the situation demands. It is a heavy responsibility but one that must be addressed by all who enjoy our hobby.
Why Destroy?
We must be quite clear at the outset of the reasons why we want to end the life of one, or several, of our charges. There can be only two acceptable reasons:
1) If the creature is clearly terminally ill, or
2) if it is already dying of old age and obviously in great distress. Ethically, there can be no other excuse.

Certainly the fishkeeper may be moving house and unable to take the fish with them, but that does not count as an acceptable reason to conveniently dispatch them down the toilet (incredulous as it may seem, it does happen)! In this particular scenario, if an aquarium has become too much of a burden, then the situation should be explained to a local retailer and the contents offered to them as a gift in return for a good home (if a payment is proffered then this can only be regarded as a bonus).

Likewise, destroying a fish or invertebrate because it is incompatible with other livestock, or just plain aggressive, cannot be excused. That is just plain cruelty. Even the culling of young fry could potentially open an ethical can of worms. For instance, is a fish of less worth, morally speaking, just because it is young? After all, if we culled young puppies, there would be a national outcry! Is there a fundamental difference?

Making A Decision
The decision to despatch a fish or invertebrate can be a difficult and painful one. Losing a dear old familiar friend is never easy and most people would prefer to hold out to the bitter end, until it expires in the course of time. This cannot be regarded as a 'natural' death as in the wild the creature would be quickly predated upon as soon as it was unable to defend itself. To prolong life in an artificially 'safe' environment can be a very unfair, not to mention dangerous course of action, for two reasons: i/ it only serves to protract the suffering and ii/ If an aquatic creature is close to death and the owner prefers to leave it to its own devices, the animal will most probably die during the night, causing a serious pollution problem that could easily result in other tankmates dying along with it before morning! Therefore, a decision must be made to despatch the creature at the opportune moment. The first task is to make sure that an accurate diagnosis has been made of the problem and assured oneself that the malady is indeed life threatening and impossible to treat effectively.

The distinctive white cauliflower growths on the fins and body of a fish are a sure sign of Lymphocystis. While such a disease can appear temporarily most disfiguring, it is rarely fatal, and an extremely unlikely candidate for euthanasia. A Hermit Crab may not have moved for a few days and cannot be clearly seen inside the shell; however, this is a common occurrence after shedding the exoskeleton and again, no reason for the animal to be disposed of! On the other hand, a chronically distressed fish lying on the bottom of a tank, covered in white spots, with gills rapidly pumping water across infected membranes, may well be a candidate for a humane dispatch, especially if all other treatments have failed.

Unfortunately, there is no precise written criteria by which the hobbyist can decide at which moment to dispose of a badly diseased animal and most aquarists will have to rely on their own judgement. Of course, a vet could always be consulted to make the decision and they will also posses the drugs by which to quickly and painlessly kill the stricken animal, should it prove necessary. Financially speaking, most hobbyists would be unable to consider the services of a vet for this sort of procedure and have to make the final decision themselves.

Fish that have stopped feeding for some considerable time, are emaciated, in very poor condition and behaving abnormally are candidates for euthanasia; as long as all best efforts have been made to revive the stricken creature. In a case such as this, it may be very unfair to let the animal continue to suffer.

Sick invertebrates are, on the whole, much more difficult to cure as there are no specific medications as such. If improvements in water quality or lighting, or both, cannot rally a deteriorating specimen then a humane end might be the inevitable course of action.

Do Fish Feel Pain?

So far, we have assumed that sick livestock, particularly fish, feel pain. Whilst comparatively little work has been done in this field, the general consensus of opinion by eminent biologists and other scientifically interested parties is that, yes, fish actually do feel pain. Therefore, any method of euthanasia must be quick and conceived to be as painless as possible.

Methods Of Fish Euthanasia
1) The quickest, but not the most pleasant admittedly, requires that the fish be held in a wet towel and hit on the head with a solid object. This is a swift end, but understandably not a popular one! If you feel that it is at all within your power to carry out the act efficiently, then this procedure is by far the most humane and practical for the average aquarist.

2) Another related method adopted by professionals in the field of fish research for the EC demands that the spinal column is severed by a scalpel, or sharp knife, just behind the neck. Death is instantaneous and must approach being as painless as could be devised.

3) Powerful anaesthetics are available from a vet and these will, at overdose levels kill the largest of livestock quickly and painlessly. These can often be administered as a soluble addition to the water holding the fish in a suitable container. Vets will often want control over this procedure so don't expect to wander into a surgery and walk out with such potent drugs! Consult a vet who specialises in fish, as not all vets do. These may located in the United Kingdom by contacting the British Veterinary Association on 0171-636 6541 (other countries will have their own association). An added complication to this method is advice from the EC committee sitting on fish euthanasia requiring that fish should be treated in situ, as any travelling would undoubtedly distress the fish even further.

4) The fish should be put into a container full of tank water, to which has been added either several tablets of Alka Seltzer, some bicarbonate of soda or baking soda. All have the effect of increasing carbon dioxide to toxic levels, putting the fish slowly to sleep and ultimately resulting in death. The drawbacks with this method are
a) knowing just how much of the substance to use in relation to the size of fish, and
b) realising that it could take a great deal of time before the fish actually expires - hours in many cases!

Note: a method once thought very acceptable by most hobbyists and experts alike was to remove the fish to the refrigerator in a sealed container of tank water. Theory had it that the fish would slowly fall asleep and die as the temperature dropped and it all seemed very humane, especially for the owner! We now know that as the temperature drops, ice crystals form within the fluids of the vital organs long before death, creating what is imagined to be a very prolonged and painful period of suffering! Whilst this method is by far the most acceptable to the majority of owners (the out of sight, out of mind school of thought), in light of this new evidence, I don't think it can be realistically supported in future.

Absolutely no work, that I am aware of, has been carried out regarding the efficient disposal of invertebrates. Do they feel pain? No-one seems to have a definitive answer, but generally speaking, it is thought most do not. It has therefore been suggested that distressed sessile invertebrates be allowed to simply dry out in the sun. Crustaceans and the like are best having their heads severed from the body with a sharp knife.
Disposing Of The Body
NEVER, NEVER flush live or dead fish or invertebrates down the toilet. It could pollute the water supply with foreign diseases (although this is more applicable to freshwater fish). More importantly though is the fact that aquatic animals can survive for a great deal of time within the sewer system (even marines) and this only serves to prolong the suffering of an already sick creature. In the case of some tropical fish, live specimens have survived to escape into the wild which could pose a threat to native fauna.

Seal up the dead animal within two, strong plastic bags (and a stout box if there are venomous spines involved) and take the package to the refuse tip and ask the attendant where best to dispose of it. Some authorities object to such matter being placed in a refuse sack, so check with the environmental health department first.

Note: resist the urge to bury the dead animal in the garden. If accidentally dug up at a later date, the fish bones, spines etc., may cause a nasty wound, especially to future owners who may be unaware that it is there.

Fish or invertebrate euthanasia is by no means a pleasant thought, but it is a job that must be done with the interests of the livestock as a priority; so, far better that the aquarist be prepared for what is an inevitable part of life than to cause unnecessary suffering by being unaware of the relevant facts.

Comments Please

The subject of aquatic euthanasia is one that understandably arouses strong feelings within the hobby. The above are my comments in the light of studying a draft report on the subject to the EC Commission. As hobbyists, your opinions are also important and can be passed onto members of the commission if so desired. If you have any opinions, please feel free to email me; although I cannot promise a response to each particular comment.

© Nick Dakin and may not be used in part, or whole, without permission.