Best Way To "kill" A Fish?

[Straydum]

garbage disposal? Also, Straydum, what type of fish is your avatar?

fire eel

 

[nmonks]

I'm with Drew on this. Subjectively, about 50% of the times I'm in touch with aquarists about destroying their fish, the only reason the fish needs to be destroyed is because the owner wants to do so. Some fishkeepers will have a fish with, say, finrot, and rather than treat the infection they'd prefer to kill the fish and get a new one. Basically comes down to money. A new fish is cheaper than buying medication. This attitude saddens me beyond words.

Not saying that's your case Tamara, I'm sure it's not, but there's also a lot of ignorance out there about how well fish can heal from seemingly severe problems. Their ability to repair damage is astounding. It's hard to imagine a plec being so sick that euthanasia was the only option -- what's the problem?

As for euthanasia methods, none of the ones available to aquarists are truly painless or known to be so, with the exception of instant decapitation. If you want to avoid causing suffering, this is one of those times where picking up the phone and talking with your vet may be in order. They can supply drugs that will kill a fish instantly and painlessly. Everything else -- ice, clove oil, etc -- may "seem" painless, but we really don't know.

Cheers, Neale

May I ask why you need to? I feel awful for you, but would feel even worse if there was something that could have been done and wasnt....

 

[Benauld]

How do these methods actually kill the fish?

Freezing = Cell death due to ice crystals forming. Painful - yes.

Clove Oil = Supposedly anaesthetic [but debatable?] For instance could any other oil be substituted, Olbas Oil for instance containing Cajuput, Clove, Eucalyptus, Juniperberry, Levomenthol, Mint and Wintergreen Oil? I would imagine the reason for death it is nothing other than the emoliant oil (i.e. when you shake it to make it white) in suspension, coating the gills and preventing oxygen from being absorbed into the bloodstream. In effect asphyxiation. Painful - debatable.

Decapitation = Severing of the spinal column. Painful - no, provided no nerves remain attached to transmit pain reception to the brain.

Alka Seltzer = Unknown to me. In water Alka-Seltzer becomes Sodium Acetylsalicylate, Sodium Citrate, and Sodium Hydrogen Carbonate. I think it might possibly be CO[sub]2[/sub] poisoning, from the effervescense. However one important point is that Alka-Seltzer contains large amounts of Aspirin, the most common cause of death following an aspirin overdose is cardiopulmonary arrest usually due to pulmonary edema. Painful - Depends upon mode of death, if aspirin then probably not. If CO[sub]2[/sub] same problems as with asphyxiation, (see above). If other ingredients - unknown.

If anybody has any info, particularly regarding possible substitutes for Clove oil I'd love to know...

**********EDIT**********
P.S. An alternative for those with CO[sub]2[/sub] kits may be to place the fish in a plastic bag with just enough water to cover it. Fill the remainder of the bag with CO[sub]2[/sub] and seal it. Hypothetically speaking, this should result in fish death quite painlessly. Although how long this method would take I do not know.
**********EDIT**********

 

[nmonks]

Clove oil is a sedative rather than an anaesthetic. I've used to to "calm" pufferfish down before trimming their teeth. The fish do indeed enter a state of torpor, where breathing slows down. Once returned to regular water without clove oil, the fish recovers almost at once in terms of breathing, and within a couple of minutes is sufficiently active to be returned to the aquarium. Seemingly, none the worse for wear, the fish doesn't exhibit any signs of severe stress, such as lack of appetite or odd colours. The fish certainly isn't happy, but no worse than if I'd netted it out and then returned it without using clove oil.

The idea with euthanising fish with clove oil appears to be the fish dies from suffocation because the fish aren't breathing, i.e., moving their gills. But whether or not the fish is conscious I cannot say. The hope is that the fish is so sedated that the effect is like a morphine overdose and the fish doesn't care its suffocating. But it could equally easily be completely conscious of the fact it couldn't breathe, but just unable to move because of the clove oil, a rather nightmarish scenario.

At the end of the day, the sharp knife / heavy hammer approach may well be the kindest, however gruesome.

Cheers, Neale

Clove Oil = Supposedly anaesthetic [but debatable?] For instance could any other oil be substituted, Olbas Oil for instance containing Cajuput, Clove, Eucalyptus, Juniperberry, Levomenthol, Mint and Wintergreen Oil? I would imagine the reason for death it is nothing other than the emoliant oil (i.e. when you shake it to make it white) in suspension, coating the gills and preventing oxygen from being absorbed into the bloodstream. In effect asphyxiation. Painful - debatable.

 

[RadaR]

At the end of the day, the sharp knife / heavy hammer approach may well be the kindest, however gruesome.

Agreed.

 

[-germ-]

Info;
The alka seltzer method is due to CO2 saturation, apparently this can also be acheived by using bicarbonate of soda.

 

[poopsydrew]

"Freezing = Cell death due to ice crystals forming. Painful - yes."

-I was under the impression that when the Ice cold water method is used, the fish is dead long before any ice crystals can form in the blood. Can anyone clarify the whole "ice crystals" myth?

Drew

 

[Kriv]

Could alcohol, by getting the fish drunk give them a quick and happy departation.

Then again, many moons ago after once watching an episode of, if I remember correctly, The Cosby Show my dad found my fish floating dead in their tank. In the show they poured a touch of Whiskey in to revive the "dead" fish and it brought them back to life.

My Dad after checking they had completely gone (not breathing, no movement etc) rather than throw them away he put the tiniest of tiny drops. No word of a lie they came back to life in 10 minutes and started swimming as normal.

Two weeks later the same happened, popped in some more whiskey and they revived again.

They died 12 weeks later, not through liver poisoning, but thanks to a neighbour house sitting and decided to move the tank into the sunlight to give them "a bit more light".

 

[Lynda B]

You're assuming that alcohol affects a fish's system the same way it would a human's. I'm not saying it doesn't because I don't know. But it might not.

 

[rdd1952]

Pavement + large rock = instant death no pain.

I have used this with tetras. It sounds very gross but as mentioned it is instant and I would think painless.

I would think the garbage disposal method would also be instant and pain free but I'm not sure exactly how a disposal works. I would assume that since everything is going down the drain and into the sewer that it would have to be pretty much totally shreded.

These 2 methods sound gross but definitely work on small fish. Personally, I would use the rock method over the garbage disposal.

 

[Lynda B]

You do not want to introduce dead fish to your water system. Especially if they've died from disease. Flushing and garbage disposals are not eco-friendly ways to dispose of the fish.

 

[backtotropical]

Are we not supposed to be 'Save the Fish' kind of people?

 

[toppman]

i killed my krib by putting in a sandwich bag and hitting it against the wall, in my opinion its the only way that i can truly say gives the fish a quick death, unless in the worst case scenario that when ur about 2 hit it u dont want 2 do it very hard then u sort of bottle out of it abit but still ending up hitting the fish not killing it 1st time, i really didnt want this 2 happen so i made sure it was a pure power blow.
saddest thing iv ever done and it really was last resort but it would of been unfair 2 keep a fish alive if its gona die slowly

 

[finchfarm]

We've only ever euthanized one of our fish. A Pacu. We don't know what was wrong with her, she started swimming all funny like she couldn't get her balanace and then she just started laying on the bottom of the tank. She wouldn't eat, wouldn't swim, and the other fish were starting to eat at her. We figured the best thing to do was put her down. My spouse works in a vets office and was able to bring some euthanazia formula home and injected her with it. I didn't want to be there for the euthanasia but I was told she was gone almost as soon as the needle was stuck in her.

I know that getting euthanazia formula like that isn't a possibiilty for everyone, and it is something I would only attempt on large fish that aren't trying to flop everywhere. For smaller fish or for those that don't have the option of using dog/cat euthanasia I don't really know what to say.

 

[Lynda B]

Are we not supposed to be 'Save the Fish' kind of people?

We are fishkeepers.... that means we take full responsibility for them, which sometimes includes the necessary task of euthanasia.

I have heard that drowning is one of the most peaceful deaths a mammal can experience. I wonder what the equivalent of that is for a fish.... merely keeping them out of water?