Fish Euthanasia

Not a pleasant subject, so why write about it? Only because many years ago I was faced with the problem of a very sick and obviously suffering fish and I couldn’t do anything about it, and couldn’t stand to see it go on. At the time those more experienced were unable to suggest the problem, but did advise on how the fish could be relieved of its misery. Thankfully I have never faced such a problem since and fingers crossed never will.

The aquarist who does all the proper things may never need to consider the subject. I feel reasonably certain that the majority of marine aquarists have never had such an awful decision to make.

The fish in question is in dire straits: it cannot breathe properly, swims in circles/upside down/up and down, bumps into things, doesn’t hide and colouration is faded. There can be several indicators. The aquarist is at a total loss to understand what the problem is, nothing fits the known diseases and ailments, and so what treatment can be given? The seawater parameters are correct, no problems. The incorrect treatment may cause more stress and suffering. Perhaps the aquarist has netted the fish out (this is easy – or was in my case – as the fish displays none of the natural instincts to hide) and put it into an isolation tank. In hope, a general anti-bacterial or copper treatment may have been tried, to no avail. Whatever the build up to the situation, it has arrived. I think aquarists would ’know’ the position.

So what to do? The fish is doomed and in severe distress. Compassion tells the aquarist to do something – there is usually only one thing to do, and that is to give the fish a quick and easier escape. How can this be done?

The only two ways I know are unsettling in themselves:

(a) Place the fish in a brown bag (I used brown as I couldn’t see the fish) and swing the bag and fish very hard against a solid surface. This will end the suffering instantly.

(b) Place the fish quickly in a small tray of ice, and leave until breathing ceases.

The second I personally am not too keen on. I’d rather have it over with quickly for the fish (and me).

Perhaps there are other and better ways of ending the suffering. If so, I’d like to know of them.

I’ll repeat what has already been stated – the aquarist may well never have this situation. Even if a fish is sick, hopefully the problem can be identified and appropriate medication applied. Our fish are remarkably resilient. The journey from the wild reef to the aquarist’s aquarium demonstrates that.


Fish Euthanasia
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6 Comments
  1. I’ve done the swinging bag trick before. Seems to have worked for me and like you said, the fish is instantly killed as long as you give it a good swing so that it is in fact instant.

  2. I have fortunately never had to do this and hope never to have to do so.

    As has been said if this has to be done then it needs to be done in as humane a way as possible.

    Whilst swinging a fish in bag as hard as you can may seem heartless and mean if it puts it out of its misery in as painless a way as possible then probably the only one feeling bad and guilty will be the aquarists him/her self.

    Personally I never ever want to have to do this.

  3. The clove oil and vodka trick seems to be very painless. I just did that on a sick one and it didn’t seem to cause any stress during the first few minutes (although I didn’t watch him until the end, so can’t say for certain).

  4. Hi Brian.
    I’ve never heard of the clove oil and vodka method.
    Could you describe how it is done?
    (Noting the vodka ingredient, I hope it isn’t just so the fish goes on its journey happy!)

  5. I do not recommd these two ways, sorry to say.

    The bag theory would cause the fish a lot of stress. You have to catch him, and bring him out of the water, and take the time to swing and hit the object. The handling and him/her being out of water causes a lot of stress on the poor fish. And then if you don’t hit hard enough the first time…

    The ice theory is alright, but still I wouldn’t do it myself. PLacing it on an ice tray still isn’t the best.

    Try looking up others, about clove oil, the vodka method, or call your vet to help put him to sleep.

  6. Glad to see you have the welfare of the fish at the top of the list.

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