happy_pitbull
Aug 26th 2007, 06:53 PM
ON THE EUTHANASIA OF FISH
This is one topic that many aquarists debate over, and that many never agree on. Over the years, I have encountered many articles and suggestions on how to euthanise a sick or dying fish, or cull a few from a batch of fry that do not meet standards and may have some deformities. In the end, I have had to make up my own mind on which way I found to be most humane and within my capabilities. I’ll give you my opinion on what I think about some methods of fish euthanasia, some of which I agree with, and others I do not. This is a somewhat emotional topic as most of us have attachments to our fish, as I do myself.
I have been keeping fish, on and off, for the last 20 years.....with a few years here and there where university, work, and the like, deprived me of money and time, making it impossible for me to stay with the hobby. But I always knew it would be a part of my life forever, as it was a passion of mine that I never grew out of.. My first tank, bought for my 10th birthday by my parents, was a 10 gallon tank....and arrived on my birthday still in the box, with a couple of goldfish in a bag...all ready to be set up!! (blame the pet store!...)...but I didn’t know then that this was the wrong way of doing things, and lucky for me I only lost one of those fish through the cycling process....even though it wasn’t until years later that learned about that process! I ended up selling that tank a few years later as boredom had set in and an offer was made and I could not turn it down. But to my surprise, the interest in fish never left me, and around 4 years later I was into it again!!! And this time I decided to research the proper methods of caring for aquarium fish, and I did a lot of reading, and still am today.
Flushing. I can say that yes, I have flushed a few fish down the toilet...but they were already dead. I always knew that flushing to dispose of a dying fish would be inhumane, as to think of the poor thing going down through the pipes..eventually to the septic tank or the sewer treatment facility....where it may suffer and hang on for who knows how long, days even...before it finally would die. Fish are pretty amazing, and even though they may be sick or almost dead, they can survive for quite some time in horrible conditions. Have you ever gone fishing, to haul in a troat or mackerel and leave it on the shore, thinking it would die immediately from suffocation?? Only to realize a half-hour later that hey, it’s still alive, mouth gapping, slowly dying. Fish are highly tolerant of hypoxia, or lack of oxygen. And a fish in the sewer is not on dry land, it is in a wet, very disgusting, contaminated environment...and think how long it could take for him to die. It is one of the cruelest methods of euthanising fish that I know of, and I cannot even call it euthanasia, as you are not putting the fish out of its’ misery, but rather increasing its’ suffering. Just because it is out of your sight, doesn’t mean it no longer exists, as humans we should be more intelligent than that. So, please..lets eliminate that as a way of euthanising any sick fish. To be even safer, do not even flush a fish that you think to be dead down the toilet...just in case :)
So, what other methods are there? Plenty, and I’m sure there are some that I have not even heard of and will not even be mentioned here because of that. But I will mention the few methods I do know of.. Eugenol, or clove oil is one I have read about, but have never used (** have used it since writing this article, and I comment on this, now my preferred method, at the end of this article**). Clove oil supposedly is quick, and painless, as it is used as an anaesthetic for fish during surgery. It causes numbness and sedation. The dosing is to add 25 drops per litre of water. It is also important to mix this first in a jar by rapidly shaking until the water turns white, as clove oil does not mix well with water. (Some people recommend adding vodka to the mix to help the clove oil dissolve into the water, but this would cause great discomfort and pain to the fish, as it would burn its skin and gills, therefore not humane). After a few seconds or so, if it has not stopped moving, you should add more clove oil to the solution. One cannot be sure of how long to leave a fish in this clove oil mixture, even after it appears dead, as it may regain consciousness afterwards if it was only sedated. After about half an hour of being “dead”, it is recommended to either place the fish in the freezer while still in the clove oil mixture, or to decapitate the fishes head, cutting directly behind the gills, to make sure it is 100% dead. It is hard for me to make a decision on this method, for if it doesn’t work right away you are to add more clove oil, and that does not seem quick enough for me. Some people find this method
unacceptable. I have no personal experience with this method, so I really cannot form an opinion. (**again, see my note at the end of this article**)
There is also Tricaine Methanosulfonate ( TMS or MS-222), a veterinary grade anaesthetic. This is used at 1 gram per litre of water, and is supposed to be peaceful and painless. I also have no personal experience with this either.
Another method that is recommended in a lot of the literature is hitting the fish against a hard surface, also known as a cranial blow. The purpose here is to destroy the brain, which instantly kills the fish. They tell you to either place the fish into a net, or get a firm grip on the fish by wrapping him in paper towel with head exposed, and slam their head, in just the right spot, against a hard surface, such as a bathtub. Now, I hate to admit to this, but I learned the hard way that this method can be extremely cruel. I had a small female Jewel cichlid who had gotten beat up pretty bad, and after a few days of trying to heal her, I new she was getting worse and only suffering. So I took my books advice, put her into a net, and ...well lets just say it took a lot more than one slam.....and it traumatized me severely, as I could not stop after starting the process of trying to kill her, to find a more humane way, as she was now suffering even more, and had to be put out of her misery immediately. It was one of the most horrible experiences I went through, and goes to show you that, no, you cannot believe everything you read . Slamming a fish against a hard surface is not always humane, as your aim and grip would have to be very accurate, and you would have to hit them in just the right spot on top of their head, and hard enough to destroy their brain.. It is probably best for larger species of fish, as the weight of the fish also comes into play.
Other methods that are recommended for larger fish involve severing their spine or breaking their neck, so to speak. I have watched many a fisherman use this method on fish including trout and mackerel . The method involves holding the fish in one hand, belly down, head pointing away from you, then using your other hand and sticking your thumb as far as it will go into their mouth and resting your hand and fingers on top of their head, than quickly and sharply snapping their head back with the hand holding the top of their mouth. This snaps their neck, is quick, and relatively painless if done correctly. I would not have the nerve to be able to do this to my fish, ever!!. I have also read about chopping a fishes head off, guillotine style. I’m sure it’s painless and quick., and that is what it is all about, to end suffering without causing anymore suffering in the process. A sharp knife, and quick hand, right behind the gills. But these above methods for the larger fish would be hard for me to do, as my attachment to the fish would make it very difficult. But then again, when ones’ fish is suffering terribly, and you have to end their pain, sometimes you have no choice.
So, what is left?? Well, the freezing method, which can be accomplished in two ways, one of which I do not agree with. This is the slow method of freezing. I would assume this to cause great stress and pain, as it involves placing the fish in a container of water into the freezer, and letting it slowly freeze to death. I do not know of any studies done on this matter, but I would think that possibly the fish can feel itself freezing, can feel the ice forming in its flesh and cells, and that this would be very painful. This may not be the case, maybe they go numb after awhile, but they would not go numb immediately, as it takes time for the water, and then the fish, to get cold enough for this. I have read of a case where somebody actually watched occasionally to see how the fish were taking it, and they thrashed around in the container, and it took over half an hour!! So they would feel some level of discomfort and stress, and very possibly pain.
Since I am unsure of the exact events that take place in slow freezing, I prefer fast freezing, as it is almost instantaneous, and works in about 1 to 2 seconds, if done correctly. This method is only useful for fish up to a certain size, say around 5 inches max. Any bigger and their mass takes too long for the cold temperature to penetrate through quickly. Take a container big enough for the fish and some, fill it with water, and freeze in the freezer until the top and sides and bottom sections of water in the container are frozen. Make sure there is still plenty of very cold unfrozen water in this container, break the ice on the surface to allow room for the fish, and then net him and submerge him quickly, holding him under in the net. If the water was as cold as suggested, the fish should be dead within a second or two. Their gills will stop moving and all fin movement ceases, and some may arch their back in death. They are completely dead, and it happens so quickly, they wouldn’t feel a thing. The quick plunge into such extreme cold conditions shocks them to death, they do not slowly freeze to death. Quick and humane. It is the actual shock to the system that kills them, and not the freezing of flesh.
Larger fish I am still somewhat unsure of how to euthanise, in a means I could handle myself.. I have never had one I had to put down that was too big to drop into ice water. I also know that goldfish and koi can withstand the colder temperatures, and their bodies actually enter a semi-dormant state in the cold. They would probably be euthanised more humanely using the decapitation method, or if all else fails, take him to your veterinarian for euthanasia, if there is one in your area that does this.
There are also some other very cruel methods that people have tried to use to put their fish down. Some I have heard of include boiling.....can you imagine?? I even hate the way live lobsters are cooked!! Adding poison to the water, such as rat poison, and others. Very cruel. Also Sodium Bicarbonate and Alka Seltzer.....with the idea being the CO2 will kill the fish, as they are being denied oxygen. I have read accounts on this, and it may work, but it is cruel as it takes quite a long period of time. Also some say to use vodka or some other strong liquor, which is also very cruel as this burns the fish’s gills, eyes and skin. I am sure there are even crueler methods out there, but I am glad that I have not heard of them. I am already disturbed enough by some of the other methods mentioned above.
So over the years I have formed my own opinions on euthanasia, and have had to deal with the matter a few times. I have found it to be an emotionally charged topic in many places on the web, and have been involved in many a discussion which eventually went sour as those involved could not agree on the best methods. It is one part of the fish hobby that nobody likes to experience, we can all agree with that. It is also interesting to read other peoples opinions on the topic. It is one of the only times a person has to kill their own sick pet, while every other pet, from snake to hamster, to birds, cats and dogs, that has to be euthanised is most times euthanised at the veterinarian clinic, not at home by the hands of their loving owners. Maybe someday there will be more veterinarians that also practice fish care, and there will be more standards to help prevent the improper care and senseless deaths of aquarium fish .
I hope some of the information written here has helped you decide for yourselves on what the best method to use is, and that maybe I have helped to stop some of the suffering out there, both to the owners and to the suffering fish.
Written in 2004
By Mindy Haight, B.Sc. Major Biology
Sources used include :
The Krib: Euthanasia (http://www.thekrib.com/Fish/euthanasia.html)
FishDoc : Anaesthetics (http://www.fishdoc.co.uk/treatments/euthanasia.htm)
Aquarticles: How to (http://www.aquarticles.com/articles/management/Haupenthal_Euthanize.html)
Plus other sources from the internet which now no longer exist.
===============================================
**
Since writing this article a few years ago, I have had a chance to use the clove oil (Eugenol) method, and I now prefer this method over the Ice water (quick freezing) method. I place 10 drops of clove oil in a small vial of aquarium water and shake rapidly to ensure the oil has mixed into solution. I then add this to the small container that I have the fish to be euthanised in, slowly. I add a few drops of the solutuion, wait a few minutes for the fish to slow some, then add a few more drops. Eventually I add all of the clove oil solution, and leave the fish in this solution for around a half hour. I then take the fish, in solution, and place in the freezer to ensure death is permament.... as sometimes fish can recover when taken from this solution. I have found this method the least stressful on the fish, and the most humane. **
Mindy Haight, August 26, 2007
This is one topic that many aquarists debate over, and that many never agree on. Over the years, I have encountered many articles and suggestions on how to euthanise a sick or dying fish, or cull a few from a batch of fry that do not meet standards and may have some deformities. In the end, I have had to make up my own mind on which way I found to be most humane and within my capabilities. I’ll give you my opinion on what I think about some methods of fish euthanasia, some of which I agree with, and others I do not. This is a somewhat emotional topic as most of us have attachments to our fish, as I do myself.
I have been keeping fish, on and off, for the last 20 years.....with a few years here and there where university, work, and the like, deprived me of money and time, making it impossible for me to stay with the hobby. But I always knew it would be a part of my life forever, as it was a passion of mine that I never grew out of.. My first tank, bought for my 10th birthday by my parents, was a 10 gallon tank....and arrived on my birthday still in the box, with a couple of goldfish in a bag...all ready to be set up!! (blame the pet store!...)...but I didn’t know then that this was the wrong way of doing things, and lucky for me I only lost one of those fish through the cycling process....even though it wasn’t until years later that learned about that process! I ended up selling that tank a few years later as boredom had set in and an offer was made and I could not turn it down. But to my surprise, the interest in fish never left me, and around 4 years later I was into it again!!! And this time I decided to research the proper methods of caring for aquarium fish, and I did a lot of reading, and still am today.
Flushing. I can say that yes, I have flushed a few fish down the toilet...but they were already dead. I always knew that flushing to dispose of a dying fish would be inhumane, as to think of the poor thing going down through the pipes..eventually to the septic tank or the sewer treatment facility....where it may suffer and hang on for who knows how long, days even...before it finally would die. Fish are pretty amazing, and even though they may be sick or almost dead, they can survive for quite some time in horrible conditions. Have you ever gone fishing, to haul in a troat or mackerel and leave it on the shore, thinking it would die immediately from suffocation?? Only to realize a half-hour later that hey, it’s still alive, mouth gapping, slowly dying. Fish are highly tolerant of hypoxia, or lack of oxygen. And a fish in the sewer is not on dry land, it is in a wet, very disgusting, contaminated environment...and think how long it could take for him to die. It is one of the cruelest methods of euthanising fish that I know of, and I cannot even call it euthanasia, as you are not putting the fish out of its’ misery, but rather increasing its’ suffering. Just because it is out of your sight, doesn’t mean it no longer exists, as humans we should be more intelligent than that. So, please..lets eliminate that as a way of euthanising any sick fish. To be even safer, do not even flush a fish that you think to be dead down the toilet...just in case :)
So, what other methods are there? Plenty, and I’m sure there are some that I have not even heard of and will not even be mentioned here because of that. But I will mention the few methods I do know of.. Eugenol, or clove oil is one I have read about, but have never used (** have used it since writing this article, and I comment on this, now my preferred method, at the end of this article**). Clove oil supposedly is quick, and painless, as it is used as an anaesthetic for fish during surgery. It causes numbness and sedation. The dosing is to add 25 drops per litre of water. It is also important to mix this first in a jar by rapidly shaking until the water turns white, as clove oil does not mix well with water. (Some people recommend adding vodka to the mix to help the clove oil dissolve into the water, but this would cause great discomfort and pain to the fish, as it would burn its skin and gills, therefore not humane). After a few seconds or so, if it has not stopped moving, you should add more clove oil to the solution. One cannot be sure of how long to leave a fish in this clove oil mixture, even after it appears dead, as it may regain consciousness afterwards if it was only sedated. After about half an hour of being “dead”, it is recommended to either place the fish in the freezer while still in the clove oil mixture, or to decapitate the fishes head, cutting directly behind the gills, to make sure it is 100% dead. It is hard for me to make a decision on this method, for if it doesn’t work right away you are to add more clove oil, and that does not seem quick enough for me. Some people find this method
unacceptable. I have no personal experience with this method, so I really cannot form an opinion. (**again, see my note at the end of this article**)
There is also Tricaine Methanosulfonate ( TMS or MS-222), a veterinary grade anaesthetic. This is used at 1 gram per litre of water, and is supposed to be peaceful and painless. I also have no personal experience with this either.
Another method that is recommended in a lot of the literature is hitting the fish against a hard surface, also known as a cranial blow. The purpose here is to destroy the brain, which instantly kills the fish. They tell you to either place the fish into a net, or get a firm grip on the fish by wrapping him in paper towel with head exposed, and slam their head, in just the right spot, against a hard surface, such as a bathtub. Now, I hate to admit to this, but I learned the hard way that this method can be extremely cruel. I had a small female Jewel cichlid who had gotten beat up pretty bad, and after a few days of trying to heal her, I new she was getting worse and only suffering. So I took my books advice, put her into a net, and ...well lets just say it took a lot more than one slam.....and it traumatized me severely, as I could not stop after starting the process of trying to kill her, to find a more humane way, as she was now suffering even more, and had to be put out of her misery immediately. It was one of the most horrible experiences I went through, and goes to show you that, no, you cannot believe everything you read . Slamming a fish against a hard surface is not always humane, as your aim and grip would have to be very accurate, and you would have to hit them in just the right spot on top of their head, and hard enough to destroy their brain.. It is probably best for larger species of fish, as the weight of the fish also comes into play.
Other methods that are recommended for larger fish involve severing their spine or breaking their neck, so to speak. I have watched many a fisherman use this method on fish including trout and mackerel . The method involves holding the fish in one hand, belly down, head pointing away from you, then using your other hand and sticking your thumb as far as it will go into their mouth and resting your hand and fingers on top of their head, than quickly and sharply snapping their head back with the hand holding the top of their mouth. This snaps their neck, is quick, and relatively painless if done correctly. I would not have the nerve to be able to do this to my fish, ever!!. I have also read about chopping a fishes head off, guillotine style. I’m sure it’s painless and quick., and that is what it is all about, to end suffering without causing anymore suffering in the process. A sharp knife, and quick hand, right behind the gills. But these above methods for the larger fish would be hard for me to do, as my attachment to the fish would make it very difficult. But then again, when ones’ fish is suffering terribly, and you have to end their pain, sometimes you have no choice.
So, what is left?? Well, the freezing method, which can be accomplished in two ways, one of which I do not agree with. This is the slow method of freezing. I would assume this to cause great stress and pain, as it involves placing the fish in a container of water into the freezer, and letting it slowly freeze to death. I do not know of any studies done on this matter, but I would think that possibly the fish can feel itself freezing, can feel the ice forming in its flesh and cells, and that this would be very painful. This may not be the case, maybe they go numb after awhile, but they would not go numb immediately, as it takes time for the water, and then the fish, to get cold enough for this. I have read of a case where somebody actually watched occasionally to see how the fish were taking it, and they thrashed around in the container, and it took over half an hour!! So they would feel some level of discomfort and stress, and very possibly pain.
Since I am unsure of the exact events that take place in slow freezing, I prefer fast freezing, as it is almost instantaneous, and works in about 1 to 2 seconds, if done correctly. This method is only useful for fish up to a certain size, say around 5 inches max. Any bigger and their mass takes too long for the cold temperature to penetrate through quickly. Take a container big enough for the fish and some, fill it with water, and freeze in the freezer until the top and sides and bottom sections of water in the container are frozen. Make sure there is still plenty of very cold unfrozen water in this container, break the ice on the surface to allow room for the fish, and then net him and submerge him quickly, holding him under in the net. If the water was as cold as suggested, the fish should be dead within a second or two. Their gills will stop moving and all fin movement ceases, and some may arch their back in death. They are completely dead, and it happens so quickly, they wouldn’t feel a thing. The quick plunge into such extreme cold conditions shocks them to death, they do not slowly freeze to death. Quick and humane. It is the actual shock to the system that kills them, and not the freezing of flesh.
Larger fish I am still somewhat unsure of how to euthanise, in a means I could handle myself.. I have never had one I had to put down that was too big to drop into ice water. I also know that goldfish and koi can withstand the colder temperatures, and their bodies actually enter a semi-dormant state in the cold. They would probably be euthanised more humanely using the decapitation method, or if all else fails, take him to your veterinarian for euthanasia, if there is one in your area that does this.
There are also some other very cruel methods that people have tried to use to put their fish down. Some I have heard of include boiling.....can you imagine?? I even hate the way live lobsters are cooked!! Adding poison to the water, such as rat poison, and others. Very cruel. Also Sodium Bicarbonate and Alka Seltzer.....with the idea being the CO2 will kill the fish, as they are being denied oxygen. I have read accounts on this, and it may work, but it is cruel as it takes quite a long period of time. Also some say to use vodka or some other strong liquor, which is also very cruel as this burns the fish’s gills, eyes and skin. I am sure there are even crueler methods out there, but I am glad that I have not heard of them. I am already disturbed enough by some of the other methods mentioned above.
So over the years I have formed my own opinions on euthanasia, and have had to deal with the matter a few times. I have found it to be an emotionally charged topic in many places on the web, and have been involved in many a discussion which eventually went sour as those involved could not agree on the best methods. It is one part of the fish hobby that nobody likes to experience, we can all agree with that. It is also interesting to read other peoples opinions on the topic. It is one of the only times a person has to kill their own sick pet, while every other pet, from snake to hamster, to birds, cats and dogs, that has to be euthanised is most times euthanised at the veterinarian clinic, not at home by the hands of their loving owners. Maybe someday there will be more veterinarians that also practice fish care, and there will be more standards to help prevent the improper care and senseless deaths of aquarium fish .
I hope some of the information written here has helped you decide for yourselves on what the best method to use is, and that maybe I have helped to stop some of the suffering out there, both to the owners and to the suffering fish.
Written in 2004
By Mindy Haight, B.Sc. Major Biology
Sources used include :
The Krib: Euthanasia (http://www.thekrib.com/Fish/euthanasia.html)
FishDoc : Anaesthetics (http://www.fishdoc.co.uk/treatments/euthanasia.htm)
Aquarticles: How to (http://www.aquarticles.com/articles/management/Haupenthal_Euthanize.html)
Plus other sources from the internet which now no longer exist.
===============================================
**
Since writing this article a few years ago, I have had a chance to use the clove oil (Eugenol) method, and I now prefer this method over the Ice water (quick freezing) method. I place 10 drops of clove oil in a small vial of aquarium water and shake rapidly to ensure the oil has mixed into solution. I then add this to the small container that I have the fish to be euthanised in, slowly. I add a few drops of the solutuion, wait a few minutes for the fish to slow some, then add a few more drops. Eventually I add all of the clove oil solution, and leave the fish in this solution for around a half hour. I then take the fish, in solution, and place in the freezer to ensure death is permament.... as sometimes fish can recover when taken from this solution. I have found this method the least stressful on the fish, and the most humane. **
Mindy Haight, August 26, 2007