How to put a fish to sleep (euthanize)

[acroman]

I think most people feel this way about freezing, but others have indicated it is painful. Are there any definitive studies or findings one way or the other?

There are several that argue that fish can't feel pain, and it (still) a topic of academic debate. Do a google search for "Can fish feel pain" and you will get an idea of what studies have found (As far as i know, there hasn't been undisputed proof on either side.)

 

[Fretfreak13]

For the people who are suggesting club soda, how do you go about doing that? Pour a bottle in a bowl and just set the fish inside it? Do you put the fish in the bowl with its own tank water and then add a certain amount of club soda? I haven't had to euthanize a fish of my own in a long time, but I work at a store and sometimes we get some in who are obviously not going to make it through shipping. Its store policy that we do not "flush" a fish until it completely dies, but rather we move it into the back of the store where it can be away from other fish picking at it and from customers that may bang on the glass to "wake him up". These are obviously not going to make it, so it'd be nice to know how to end it faster for them, other than feeding them to a grouper or another fish that swallows food whole rather than tearing at it, like a trigger. Sometimes the little victims are just too large to do that.

 

[kegogut]

Give em' the chop. It might be harder for some people than say freezing or something but its way easier on the fish.

 

[Reeferz412]

Give em' the chop. It might be harder for some people than say freezing or something but its way easier on the fish.

thats what I was taught to do and still do. Simple, clean, and quick.

 

[Megatrev62]

Slam the fish on the road. Or slice his head clean off. That is instant.

 

[Reeferz412]

Slam the fish on the road. Or slice his head clean off. That is instant.

Slamming the fish on the road does not work, it kinda stuns it tbh.... I have seen fishermen do this on the pier and throw it in the water, it kinda just floats there stunned.

 

[Megatrev62]

Slamming a fish on the road or concrete floor kills them for me. When trouting I just break their necks by pulling back hard on their head. Immediate kill. Throw them against a rock works good too.

 

[ladyshark]

I've done the club soda and it works pretty quickly.. Never heard of the clove oil.. QUOTE]

Based on advise on this thread, I just used the club soda method. My fish panicked and seemed desparate to get out of the water. It was horrible.


After about a (long) minute he seemed dead, but still twitching. As I look over to him now, still very minor twitching (10 minutes later).

It appears to be a slow, uncomfortable (not sure about pain) death. I am horrified, and will never forget it or forgive myself.

DO NOT USE CLUB SODA. WHAT A DISASTER!

Those of you giving advise, please, please know that people like me without a lot of experience are relying on you, this is our research.

Please, please be specific, don't add things later as an afterthought and assume we know what you mean.

Someone is going to tell me I did something wrong. Please don't. I am devastated.

 

[slapshot]

Not gona say you did something wrong but did you add the soda water to a bowl of tank water? They just fall asleep. The twitching you saw, is not a big deal he is asleep. Just be sure you add enough to do him in at the end. I add a little at a time until they go to sleep then pour in a bunch

 

[kegogut]

I've done the club soda and it works pretty quickly.. Never heard of the clove oil.. QUOTE]

Based on advise on this thread, I just used the club soda method. My fish panicked and seemed desparate to get out of the water. It was horrible.


After about a (long) minute he seemed dead, but still twitching. As I look over to him now, still very minor twitching (10 minutes later).

It appears to be a slow, uncomfortable (not sure about pain) death. I am horrified, and will never forget it or forgive myself.

DO NOT USE CLUB SODA. WHAT A DISASTER!

Those of you giving advise, please, please know that people like me without a lot of experience are relying on you, this is our research.

Please, please be specific, don't add things later as an afterthought and assume we know what you mean.

Someone is going to tell me I did something wrong. Please don't. I am devastated.

Sorry to hear about your experience. I agree that some people just give advise based on what they think would work and not what they have tried successfully. :headwally:

As I was saying earlier the most humane way to put a fish down is decapitation. Its not something for the faint of heart but in the big picture its not really about you,its about the:fish1:

 

[ladyshark]

I didn't feel capable of decapitation, but now i think it might have been better (still not sure I could do it). Also, i know a lot of my upset feeling is simple grief over losing this little guy. I just knew he would not get better-he was the first fish I ever had to treat. I feel awful. Probably added it too quickly. He was in a 10 gallon hospital tank. I just didn't realize, thought it would be peaceful and fairly quick. Poor little guy. I hope I am never confronted with this again.

Thanks for your thoughts.

 

[Reeferz412]

I didn't feel capable of decapitation, but now i think it might have been better (still not sure I could do it). Also, i know a lot of my upset feeling is simple grief over losing this little guy. I just knew he would not get better-he was the first fish I ever had to treat. I feel awful. Probably added it too quickly. He was in a 10 gallon hospital tank. I just didn't realize, thought it would be peaceful and fairly quick. Poor little guy. I hope I am never confronted with this again.

Thanks for your thoughts.

Decapitation is a very quick method. I would say the fish is alive for a few second if you want me to be honest. But sometimes its dead instantly. Sorry for your terrible experience. I personally cannot see myself freezing a fish. I think my girlfriend would freak out if she saw a fish in the freezer.

 

[acroman]

http://www.fishchannel.com/fish-health/euthanasia.aspx

This is a pretty decent article with common methods used for humane euthanasia in fish.

If you decapitate, make sure to crush the brain (pithing.)

 

[mperales]

ladyshark wrote:

Based on advise on this thread, I just used the club soda method. My fish panicked and seemed desparate to get out of the water. It was horrible.


After about a (long) minute he seemed dead, but still twitching. As I look over to him now, still very minor twitching (10 minutes later).

I'm sorry for the experience that you had.
In a lot of animals an excitatory phase is very common before sedation takes effect. That is what you were probably seeing in your fish.

The American Veterinary Medical Association (AVMA) has some guidelines for what it considers acceptable euthanasia. It divides the process into mainly 2 sections chemical vs physical. I'll try to highlight what it is recommended per the AVMA Guidelines for the Euthanasia of Animals: 2013 Edition

1) IMMERSION AGENTS:

a) Benzocaine or benzocaine hydrochloride, buffered. Solutions for immersion should be prepared in concentrations 250 mg/L and should be buffered.

b) Carbon dioxide. Immersion in CO2-saturated water causes narcosis and loss of consciousness after several minutes. Some species may exhibit hyperactivity prior to loss of consciousness. Purity and concentration of CO2 are important for effectiveness. Only CO2 from a source that allows for careful regulation of concentration, such as from cylinders, is acceptable.

c) Ethanol. Ethanol has been suggested as an acceptable alternative method for finfish. The depressive effects of ethanol on the CNS are well described and exposure of zebrafish via immersion has become a model for behavioral and molecular responses to alcohol, at concentrations from 10 to 30 mL of 95% ethanol/L. At this dose, alcohol induces anesthesia, and prolonged immersion produces death via respiratory depression causing anoxia. This is not equivalent to immersing finfish directly into preservative concentrations of ethanol (70%), which is not acceptable as a euthanasia method.

d) Eugenol, isoeugenol, and clove oil. Whenever possible, products with standardized, known concentrations of essential oils should be used so that accurate dosing is possible. Concentrations required for anesthesia will vary depending on species and other factors, but may be as low as 17 mg/L for some species. Greater concentrations will be required for euthanasia.
Finfish should be left in the anesthetic solution for a minimum of 10 minutes after cessation of opercular movement. These compounds are equivocal or known carcinogens according to the National Toxicology Program.

The other agents mentioned are controlled/not available to the public.

2) PHYSICAL METHODS:

a) Decapitation followed by pithing (2 step). Rapid severance of the head and brain from the spinal cord, followed by pithing of the brain, will cause rapid death and unconsciousness. Decapitation alone is not considered a humane approach to euthanasia, especially for species that may be particularly tolerant of low O2 concentrations. Pithing helps ensure rapid loss of brain function and death for those species.

b) Cervical transection using a knife or other sharp instrument inserted caudal to the skull to sever the spinal cord and cervical vertebrae, followed by pithing (2 step). The rationale for this approach is similar to that for decapitation (destruction of connections between brain and spinal cord) and pithing (destruction of brain tissue), except that the head is still physically
attached by musculature to the body

c) Manually applied blunt force trauma (cranial concussion) followed by pithing (2 step). Manually applied blunt force trauma (a rapid, accurately placed blow of sufficient energy to the cranium with an appropriate-sized club) can cause immediate unconsciousness and potentially death, but should be followed by pithing to ensure death. The finfish’s size, species, and anatomy and characteristics of the blow (including its accuracy, speed, and club mass) will determine the efficacy of manually applied blunt force trauma. This procedure requires training and monitoring for proficiency. Anatomic features, such as the location of the eyes, can help serve as a guide to the location of the brain

d) Captive bolt (most commonly nonpenetrating; 1 step). This is a method usually applied to large finfish species.

e) Maceration (1 step). When applied correctly, using a well-maintained macerator specifically designed for the size of finfish being euthanized, death is nearly instantaneous. The process is aesthetically unpleasant for some operators and observers

f) Rapid chilling (hypothermic shock; 1 step or 2 step). It is acceptable for zebrafish (D rerio) to be euthanized by rapid chilling (2° to 4°C) until loss of orientation and operculum movements316,461,462 and subsequent holding times in ice-chilled water, specific to finfish size and age. Zebrafish adults (approx 3.8 cm long) can be rapidly killed (10 to 20 seconds) by immersion in 2° to 4°C (36° to 39°F) water. Adult zebrafish should be exposed for a minimum of 10 minutes and fry 4° to 7 °F for at least 20 minutes following loss of operculum movement...
...Until further research is conducted, rapid chilling is acceptable with conditions for other small-bodied, similarly sized tropical and subtropical stenothermic species. Species-specific thermal tolerance and body size will determine the appropriateness and effectiveness of rapid chilling for euthanasia of finfish. Finfish size is important because the rate of heat loss via thermal conduction from a body is proportional to its surface area. Based on these 2 factors, it has been suggested that rapid chilling in water associated with an ice slurry is a suitable killing method for small tropical and subtropical finfish species 3.8 cm in length (tip of the snout to the posterior end of the last vertebra) or smaller, having lower lethal temperatures above 4°C. To ensure optimal hypothermal shock (ie, rapid killing), transfer of finfish into ice water must be completed as quickly as possible. This means rapid transitions from acclimatization temperature to 2° to 4°C must be achieved. This can be accomplished by using minimal water volume to transfer finfish (ie, using a net to place finfish in chilled water). In addition, finfish should not be in direct contact with the ice in the water; rather a depression should be formed in the ice slurry to expose the entire surface of the finfish to the chilled water. Full contact with cold water ensures optimal exposure and rapid chilling of the finfish temperature must not exceed 2° to 4°C. Well-insulated containers, such as coolers, will assist in maintaining the ice slurry and a probe thermometer can be used to confirm water temperature. This method of euthanasia is not appropriate for temperate, cool, or cold-water–tolerant finfish, such as carp, koi, goldfish, or other species that can survive at 4°C and below.

 

[mperales]

I apologize. Benzocaine is not available to the public / OTC

 

[good_reefer]

take fish and wrap gently in toilet paper

Flush !!!!!!!:lmao:

bigger fish - dig hole under most favorite plant

Feed!!!!!!:fun4:

 

[mperales]

take fish and wrap gently in toilet paper

Flush !!!!!!!:lmao:

AVMA has that covered also. :lmao:

The following are unacceptable methods of euthanasia in any situation. Flushing of finfish into sewer, septic, or other types of outflow systems is unacceptable for many reasons. Water chemistry and quality may delay time to death and result in exposure to noxious compounds. For systems in close proximity to and/or connected to natural waterways, pathogen release or transmission may occur from diseased or carrier animals. . Similarly death by anoxia and dessication after removal from the water or by anoxia in water; any death due to exposure to caustic chemicals; and death including prolonged traumatic injury prior to unconsciousness are unacceptable.

 

[billsreef]

I apologize. Benzocaine is not available to the public / OTC

Not sure why it's not mentioned, but Tricaine, aka MS-222, aka Finquel as long been the standard for euthanasia in research labs working with fish...as well as an anesthetic. It's also readily available from places like Aquatic Ecosytems, and I believe even Drs. Foster and Smith has it in small quantities.

 

[mperales]

Not sure why it's not mentioned, but Tricaine, aka MS-222, aka Finquel as long been the standard for euthanasia in research labs working with fish...as well as an anesthetic. It's also readily available from places like Aquatic Ecosytems, and I believe even Drs. Foster and Smith has it in small quantities.

Bill, the omission was my doing. I was trying to just post the ones that I thought were readily available to everyone. I did not know Tricaine was available OTC. Some of the websites I searched said a prescription from a Veterinarian would be needed (?) and some did not mention it.

Here is the info on Tricaine /MS-222:

Tricaine methanesulfonate, buffered (MS 222, TMS). Solutions must be buffered, and concentrations required for euthanasia may vary depending upon the species, life stage, and water chemistry parameters. A concentration of 250 to 500 mg/L, or 5 to 10 times the anesthetic dosage, is effective for most species. MS 222 at a dose of 400 mg/L has been shown to be ineffective for a few species (eg, Gulf of Mexico sturgeon). Finfish that are too large for practical or cost-effective immersion in lethal doses of buffered MS 222 can be euthanized by applying the concentrated, buffered solution directly to the gills

 

[jenglish]

To add a little to the discussion on decapitation; pithing is required due to the tolerance for low oxygen in cold blooded species. So if you cut my head off with a guillotine, the instant loss of blood pressure would render me unconscious nearly instantly. The same does not hold true for fish, amphibians and reptiles.

I would recommend MS-222 or clove oil as being easier for most folks to watch. If you feel you that you are not sure it is dead after one of these methods another method can be used as a follow up, knowing the fish is at least not feeling pain.