What's new

Euthanizing FW Fish

🐠 March TOTM Starts Now! 🐠
FishForums.net Tank of the Month!
Click here to enter!
I purchased clove oil from Amazon last evening. It will arrive today.

I hope you never need to use it! But it's good to have it on hand, in case.

@Seisage while pithing might work in research labs or similar, with people who know what they're doing, I wouldn't have a clue! But that's why when I didn't have clove oil, I used the paper towels and heavy book method. Not a nice experience to do, but I at least knew it would be over for the fish instantly.


But I can absolutely understand someone not being able to do that, and it feels horrible to do. At least with clove oil, it feels more like when you sadly have to take a dog/cat/other pet to a vet to be euthanised. A sedative so they're peacefully sleeping, then overdose to stop the heart and breathing while they're asleep and no longer suffering at least.

I've heard of adding a little vodka at the end, to be absolutely sure the fish has passed? Or would some drops of that in the first clove oil/water mix help the oil and water combine more? I forget the scientific word for that process, I haven't slept, and that paper is above my intellectual capacity I'm afraid! I need it explained to me as if I'm about ten years old, I'm sorry!
 
I hope you never need to use it! But it's good to have it on hand, in case.

@Seisage while pithing might work in research labs or similar, with people who know what they're doing, I wouldn't have a clue! But that's why when I didn't have clove oil, I used the paper towels and heavy book method. Not a nice experience to do, but I at least knew it would be over for the fish instantly.


But I can absolutely understand someone not being able to do that, and it feels horrible to do. At least with clove oil, it feels more like when you sadly have to take a dog/cat/other pet to a vet to be euthanised. A sedative so they're peacefully sleeping, then overdose to stop the heart and breathing while they're asleep and no longer suffering at least.

I've heard of adding a little vodka at the end, to be absolutely sure the fish has passed? Or would some drops of that in the first clove oil/water mix help the oil and water combine more? I forget the scientific word for that process, I haven't slept, and that paper is above my intellectual capacity I'm afraid! I need it explained to me as if I'm about ten years old, I'm sorry!
If I used the paper towel and heavy book method, I would have to drink the vodka and clove oil just to collect my nerves again. :)
 
If I used the paper towel and heavy book method, I would have to drink the vodka and clove oil just to collect my nerves again. :)
Haha! I promise, you wouldn't want to drink the clove oil once you smell it! But yeah, having the vodka on hand might be useful in more ways than one, for sure! But I'd recommend orange juice or tonic as a mixer rather than the clove oil... ;) :lol:

Felt like a monster doing it. But I also know it was instant for the poor guppy. But when your nature is to care for animals, it made me feel like an awful person to do it - yet I also know, on a logical, intellectual level, that while I hated it, it was better for that guppy than the slow and painful death he was experiencing, and better than just leaving him in the tank to die painfully.

It is a difficult topic, since it's a horrible thing to think about. But I'm glad the thread was made, because sadly sometimes we do need to do something to prevent further suffering, and trying to find the most humane ways known, that can be shared when others are facing a similar hard decision, is a good thing.
 
I have a hard time killing anything, even bugs. Ants and termites may be the exceptions. But when they invade one's home, it means war.

There is a difference when using clove oil as an anesthetic v.s. an agent for euthanizing. For smaller fish it can work as both. But is needs to be done in states where the first is as an anesthetic. It can be use for this with larger fish as well. Apparently, it becomes more difficult to use as a killing agent as the size of the fish gets larger.

Also, as an anesthetic it can be a bit less reliable in terms of effect and duration as well as recovery time compared to the chemical agents normally used for this purpose.

squeamish
adjective
us/ˈskwiː.mɪʃ/ uk/ˈskwiː.mɪʃ/
easily upset or shocked by things that you find unpleasant or that you do not approve of:
She's really squeamish and can't stand the sight of blood.
Many cooks are squeamish about putting live shellfish into boiling water.
 
I have a hard time killing anything, even bugs. Ants and termites may be the exceptions. But when they invade one's home, it means war.

I'm usually the kind of person who will feed a sluggish bee some sugar water and watch them until they're recovered and can fly away! I've grown up taking in waifs, strays, rescues, and if I may permit myself a little brag here - usually pretty good at it! Even as a kid when my dad bought home a baby pigeon, I woke every 3-4 hours nightly to help with his feedings!

The real phobia I have (besides agoraphobia/other humans... bah) is spiders, and I've always hated that I'm scared of them! Even as a kid. Wasps, bees, rats, snakes, any other creepy crawlie? No worries! I'd keep pet rats, they're wonderful pets, so I hated that I had such a stereotypical "girlie" fear. So any time I had a chance, I'd challenge myself, like being the first to step up when given the chance to hold a Goliath Bird eating spider that needs two hands to hold (which is a pretty fun story for another time). I learn about them to reduce my fear, admit that they're also fascinating creatures in their own right, eat the more annoying bugs etc. Which does help reduce the fear response, even though that initial heart stop and GAH reaction is still there if a large house spider or something surprises me. So even spiders, I'll make myself pick up and relocate usually, or find a glass and some card if it's a scary one!

I don't enjoy or relish the idea of killing something, and I definitely didn't have an easy time doing it. But it was about the welfare of the fish, not my own, ya know?
 
@Seisage while pithing might work in research labs or similar, with people who know what they're doing, I wouldn't have a clue!
Yeah, that's the downside of pithing. It's a bit more advanced technique. I don't know exactly how to do it either, to be honest. I'm sure there are video tutorials out there if you can stomach watching them. I think I'd only attempt pithing if I didn't have clove oil on hand and my primary euthanasia method had to be decapitation.

I've heard of adding a little vodka at the end, to be absolutely sure the fish has passed? Or would some drops of that in the first clove oil/water mix help the oil and water combine more? I forget the scientific word for that process, I haven't slept, and that paper is above my intellectual capacity I'm afraid! I need it explained to me as if I'm about ten years old, I'm sorry!
You might be thinking of emulsifying! Indeed, alcohol is a much better medium to mix oils into, since oils and other fats are much more soluble in alcohol. When you do the vigorous shaking method with the clove oil in water, all that does is create teeny tiny oil droplets that are simply suspended in the water. If you left it on a counter for a while, the oil droplets would come together again eventually. The water and oil is never truly mixed. With alcohol, it's an actual chemical process, and no amount of sitting will allow the oil to separate from the alcohol. I think that's why McGill University specifies the use of alcohol in their protocol.
 
Yeah, that's the downside of pithing. It's a bit more advanced technique. I don't know exactly how to do it either, to be honest. I'm sure there are video tutorials out there if you can stomach watching them. I think I'd only attempt pithing if I didn't have clove oil on hand and my primary euthanasia method had to be decapitation.


You might be thinking of emulsifying! Indeed, alcohol is a much better medium to mix oils into, since oils and other fats are much more soluble in alcohol. When you do the vigorous shaking method with the clove oil in water, all that does is create teeny tiny oil droplets that are simply suspended in the water. If you left it on a counter for a while, the oil droplets would come together again eventually. The water and oil is never truly mixed. With alcohol, it's an actual chemical process, and no amount of sitting will allow the oil to separate from the alcohol. I think that's why McGill University specifies the use of alcohol in their protocol.

Emulsifying! That was the word I was hunting for, thank you! I've been talking a lot about redecorating recently, and the word "emulsion" kept popping into my head. I knew that that was paint, but brain fog said "don't even google, we all know oil and water don't mix without chemical assistance", but blanked on the term, thank you!

Okie doke then, time to add a vodka mini or two to my "emergency use only" box of kit in my fishstand then, and hope people don't think I'm developing a problem... ;)

I was curious about an emulsifying agent, and whether the droplet sizes of clove oil might also account for the differences when people find a fish panics, while others don't. Although of course, the nature and stage of the illness of the individual fish might account for that too. But when I've shaken and added the clove oil mixture, of course it's more like droplets of oil briefly suspended in the water, and importantly, droplets of different sizes too. If the fish breathes a larger droplet or two through it's gills, it's going to be getting a different dose at a different rate of course, and since the oil and water aren't truly mixed evenly, even having a number of droplets of oil to use per litre of water is still going to lead to varying results without that emulsifier.
 
I was curious about an emulsifying agent, and whether the droplet sizes of clove oil might also account for the differences when people find a fish panics, while others don't. Although of course, the nature and stage of the illness of the individual fish might account for that too. But when I've shaken and added the clove oil mixture, of course it's more like droplets of oil briefly suspended in the water, and importantly, droplets of different sizes too. If the fish breathes a larger droplet or two through it's gills, it's going to be getting a different dose at a different rate of course, and since the oil and water aren't truly mixed evenly, even having a number of droplets of oil to use per litre of water is still going to lead to varying results without that emulsifier.
You know, I think you could be onto something here! I'm honestly not sure if there's any research that looks into this, but it makes a lot of sense. The inconsistency and unevenness of the suspension could very well be contributing to an excitable/panicked response. Even if the differences in oil droplet sizes don't appear large, most hobby fish are rather small creatures, so I imagine it really could make a difference for them.

I hope to not have to test this out myself anytime soon, but yes, I'll definitely also have to grab some cheap high proof vodka for a little emergency kit.
 
You know, I think you could be onto something here! I'm honestly not sure if there's any research that looks into this, but it makes a lot of sense.

Yay! I was always strong in biology, but absolutely awful at maths, physics and chemistry, so couldn't really be a proper scientist, even if I'm one at heart! But my lack of ability in the latter subjects always bothered me, and made me feel as though I must be stupid, or defective somehow.

But my brilliant, kind, wonderful, polymath mentor turned friend when I returned to college as a mature student pre-University, who helped me not only get through, but get top marks for the statistics parts of my course, all the while insisting that I was "a scientist by nature, currently in training and with a brilliant mind", said that my potential dyscalculia (they picked up that I occasionally switched digits without realising, but since I don't have dyslexia, and the two are often (but not aways) linked or comorbid, hadn't been picked up on before) wasn't the main thing. That I grasped the concepts behind the subject matters we were trying to analyse, articulate what I'd like to test (my major project ended up being a statistical analysis of the general publics beliefs about evolution and religion, and the potential conflicts therein), why, and how the information could be useful if it proved to be statistically significant, etc... that I could grasp the bigger picture and ask the right questions, and that having computers run the actual tests is simple, can be learned, but that the bigger picture stuff, the ability to look at the variables and spot potential errors in methodology etc, the critical thinking parts, are all there. :D

I'm still so sad that I was only able to know him for a few years before his passing, but he was a wonderful teacher, and soul. A natural polymath, yet exceedingly humble while building up others, and a genuine joy and passion for life, learning, and teaching. Miss that man, and this made me think of him again, so thank you for that wonderful encouragement, and reminder. ♥️
 
Here are the sources if people are interested
Paper (only abstract available): https://pubmed.ncbi.nlm.nih.gov/27683808/
Notre Dame University guidelines (equivalent to AVMA guidelines): https://freimann.nd.edu/assets/262662/fullsize/iacuc_clove_oil_aneseuth_pol16_2_.pdf
AVMA guidelines for animal euthanasia (eugenol/clove oil is on page 38): https://www.avma.org/sites/default/files/2020-02/Guidelines-on-Euthanasia-2020.pdf
McGill University guidelines: https://www.mcgill.ca/research/file...atic_amphibian_euthanasia_-_march_2022_v2.pdf

You can read the full paper for the first one listed above: https://www.scielo.br/j/bjb/a/4xZbdnymXTQLMvchbXp76mx/?lang=en

The one thing that seems to be common practice in most of what I read no matter what method one chooses to deliver the final death, one should anesthetize the fish first. I doubt if we have to chase a fish around the tank to catch it, then we move it somewhere hostile to smash it, cut off its head or stab it's brain or use clove oil stronger annesthetic to induce death that the fish did not have an unpleasant experience with no anesthetic used.

But consider this from Wiki:
Decapitation is quickly fatal to humans and most animals. Unconsciousness occurs within 10 seconds without circulating oxygenated blood (brain ischemia). Cell death and irreversible brain damage occurs after 3–6 minutes with no oxygen, due to excitotoxicity.

And then there is this as well from Humane Slaughter: Atlantic salmon
Fish must be stunned (or dead) before they are decapitated, and when stunned should remain insensible until death supervenes. This is because decapitation does not instantly kill and consciousness is not lost immediately.

What upset me the most about the experience I reported in my initial post was it was clear to me that when I started to adminiter the initial Clove pit the fish reacted ppoly. It was clearly "not happy." I think this was my fault for not administering the anesthetic dose slowly enough. From what I can tell there is a blance hetween how much clove oil is added and how slowly to do it so there is no discomfort to the fish as there will be some anesthetic effect which we increase as we work up to the full anesthetic dosing.

Another way to put this would be, go slow so you know you know you are not "hurting" the fish before it goes to sleep.

Understand that when professionals have to euthanize a fish they mey use an injection. For most of us this is not an option. If I must put down a fish, I want to do so as kindly as I possibly can.
 
I have read many accounts about how to euthanize fish. But from personal observations the quickest methods seem to cause the least additional distress to the fish. In addition, one of the documents provided above one mentions 3 pathways to euthanize the animals, one is physical disruption of the brain activity, which they considered might be the best for the fish.

I know it is not pleasant but quickly dashing the fish against a hard surface is quick and effective. From the time the fish is in the net till death is less than 10 seconds (and that is all in the transportation), the fish is stunned with the impact, and all the other biological systems are also destroyed nearly instantaneously. This method is not good for people who cannot physically put enough force and control into dashing the fish, or for people who cannot stomach such a method, but from the fish's perspective they go from the net to non-existence very quickly.

The concerns I personally have with using clove oil are mostly to do with the dosing, we have some guidelines for specific fish, but for most we do not know what the ideal dose is, and even if we have the dosing what is the concentration of the active ingredient in the clove oil we purchased, overall dosing is a bit of a crap shoot. Additionally, the fish has to be transported and place into a smaller vessel where the water likely tastes/feels? different, overall the experience may be easier on us as the fish keeper but is it easier on the fish? Clove oil is an irritant does that affect the fish? I remember getting an IV of some magnesium salt and feeling the inside of my veins burning, what does clove oil do to the sensitive membranes in the gills? These are questions I don't see answered in the various documents, they seem to focus on recovery times and lethality.

I would use clove oil to try to anesthetize a fish to do surgery, but that is where there is a hope of a future life for a fish. And I would use clove oil for larger fish where dashing would be less guaranteed to be effective, i.e. something Oscar sized, we have to be pragmatic. I am not against the use of clove oil in general, but I believe there are more effective means of euthanizing the smaller more common types of tropical fish we keep.
 
Well, the fish I had to put down was a small tetra. I am not sure one could hold onto it to smash it on hard surface. And if I put it between a folded piece of foi;l the result would have been tetra jelly shooting out of the foil.
 
Well, the fish I had to put down was a small tetra. I am not sure one could hold onto it to smash it on hard surface. And if I put it between a folded piece of foi;l the result would have been tetra jelly shooting out of the foil.

When I used the method with the guppy, I used disposable paper towel. a few sheets folded and prepared on the table next to me, large heavy book at the ready. I netted the guppy calmly, quickly and easily (guppies at least are super easy to catch), turned the net out onto the paper towel and folded the other paper towel over the top of him so he was in the middle, slammed with the book.

It would have taken less than ten seconds before he went from struggling to swim and gasping/ailing, to net, then game over and brain/nervous system destroyed instantly. No mess, all contained within the sheets of paper towel, and I dispose of deceased fish in the general waste anyway since flushing and burying pose potential environmental contamination issues. Although I have buried some favourite fish and certainly my first few, before I learned here not to do that.

Feels mean to do it, and I agree with @Uberhoust that the fish barely has time to register anything before it's over for them.

However, that's with small fish like livebearers and tetra, I honestly don't know now what I would do it faced with euthanising a larger fish. I also completely understand that a lot of people couldn't bring themselves to do it, and I won't judge them for that.

I used the clove oil method on a pretty large goldfish from the pond that was suffering and dying, but slowly, without problems. But the video I watched to learn how to do it did stress the importance of adding it gradually, so I agree with you @TwoTankAmin , and @Uberhoust , that the accounts I've read here from people who've reported a panic response seem to have added a lot of clove oil too quickly.

I'm even more confused and undecided on most humane methods now. I feel like handling a fish in order to pith it would be much more stressful for them, and take more time to aim, if you even know where to aim, and most of us don't. Decapitation not instantaneous, and probably even harder for most people to do than the heavy book method. Personally I think I'd find it harder to behead one of my fish than the folded paper towel and book.

And yeah, we can't truly know if the clove oil feels irritating to the fish. But it is at least seemingly peaceful if the oil is added gradually, a clean container and water from the tank, oil mixture added gradually, and it does sedate them, seemingly without panic if done gradually, and better than being left to die slowly and painfully of organ failure or something.

Trust me, from very recent personal experience, and several years spent working in nursing homes - the active dying process when organs are shutting down is painful and distressing for the patient in humans, and we do everything we can to manage it with incredibly strong medications to ease their suffering and allow patients to pass as painlessly and comfortably as possible, and even in humans, it's difficult and not precise, but leaving them to go through that without anything to ease that suffering would be awful.

So when a human or typical pet mammal like a dog or cat has reached the active dying stage, we use strong medications to manage the pain and other symptoms of various organs shutting down, and/or veterinary euthanasia.

But even when vets euthanise a dog or cat, and sedate them first, it doesn't always go as hoped. Having had a lot of animals, and wanting to be there to comfort them right to the end, I've witnessed more dogs and cats being put to sleep than I want to count right now, and fortunately, it's always been peaceful and a relief for the pet, and us, in that we knew it was the right time, and to prevent them suffering (any more). But the vets do always warn that sometimes, an animal will react poorly to the euthanising agent or the sedative. It's not foolproof, sometimes the animal reacts, and it's distressing for the owners, but the vet will obviously then do whatever they can to help the animal pass as quickly as possible.

Should mention at this point that vets have a very high suicide rate, statistically. It's not an easy job, and I'm so glad I didn't go into that field the way I wanted to as a child.

So I can't leave a fish to die slowly and painfully, and realistically, we do have to face this decision at times, especially keeping many fish, and trying to help people on the forum who have a dying fish and don't know what to do. It would be good if we could have more advice, and the research you guys are putting in is appreciated!
 
I'm even more confused and undecided on most humane methods now. I feel like handling a fish in order to pith it would be much more stressful for them, and take more time to aim, if you even know where to aim, and most of us don't. Decapitation not instantaneous, and probably even harder for most people to do than the heavy book method. Personally I think I'd find it harder to behead one of my fish than the folded paper towel and book.
Oh! I should clarify! Pithing is done as a secondary euthanasia method ONLY. It should never be done on a live animal. Only once it's decapitated or otherwise euthanized should one attempt pithing. I think most of the pithing methods are designed to be done after decapitation.
 

Most reactions

trending

Staff online

Back
Top