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Old 03-29-2023, 10:39 PM   #1
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Unhappy What is the proper way to put dying fish asleep?

What is the proper way to put dying fish asleep? Is it ok to put the fish in the freezer. Is that humane, or is there another way to put fish to sleep? I do not have any vodka on me. I put one of my fish in the freezer, but I want to know is that ok to do? The fish was dying. I did not know what else to do. If i need to go out and buy some Vodka, just let me know. I keep loosing fish, they keep dying.
I test my water and all is fine, there no ammonia in my tank. no Nitrite. Nitrate is 0.. it was 40ppm. But I did a water change. My ph is 7.4
I lost all my guppy fish. I had 10 of them.
I lost some Cory Fish, and a few Glo Tetra's.
I'm still not going to buy anymore fish.
Right now I have:
6 glo fish
4 tetra fish
5 Blue Spotted Cory fish
4 Panda cory

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Old 03-30-2023, 12:02 AM   #2
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Fact is, if your tank was cycled, you would have some nitrate. That is not a bad thing as nitrate is not toxic if not in really high amounts.
Besides, some nitrate is necessary for a planted tank.
Do not confuse nitrate with nitrite which is toxic to fish.
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Old 03-30-2023, 01:47 AM   #3
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Old 03-30-2023, 01:55 AM   #4
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The quickest way to kill a small fish is to wrap it in a paper towel and hit it on the head with something hard. The drawback is it can be messy.

Clove oil mixed with a small amount of alcohol can be added to a small container of water containing the sick fish. You have the water aerated gently and add a drop of clove oil, wait about 20-30 seconds and see how the fish responds. If it continues to swim you add another drop and wait a bit. Continue doing this until the fish stops swimming and sinks to the bottom. Then add a few more drops and pop the container of water in the freezer. Leave until frozen solid then bury the iceblock in the garden.

If you can't get clove oil (available from most chemists/ pharmacists or online) and you can't bring yourself to hitting a fish on the head, put them in a small container of aquarium water and put a lid on it. Put it in the freezer and walk away. Bury the iceblock after it's frozen solid.

Freezing isn't the nicest way to kill them but it's the easiest for most people.

Clove oil is good if you can get it.

The following links are about euthanising/ sedating fish and might interest you.



Ammonia, nitrite and nitrate are all forms of nitrogen and are all toxic to fish and other aquatic organisms. Ammonia is the most toxic (especially in water wiht a pH above 7.0), followed by nitrite (more toxic in water with a pH below 7.0), and then nitrate.

Ammonia and nitrite have to be kept at 0ppm at all times.
Nitrate should be as close to 0ppm as possible and under 20ppm at all times. Nitrates do cause long term damage to fish health. Whereas ammonia and nitrite tend to kill fish quickly.


Test the water for ammonia, nitrite, nitrate and pH.

Wipe the inside of the glass down with a clean fish sponge. This removes the biofilm on the glass and the biofilm will contain lots of harmful bacteria, fungus, protozoans and various other microscopic life forms.

Do a 75% water change and gravel clean the substrate every day for a week or until the problem is identified. The water changes and gravel cleaning will reduce the number of disease organisms in the water and provide a cleaner environment for the fish to recover in. It also removes a lot of the gunk and this means any medication can work on treating the fish instead of being wasted killing the pathogens in the gunk.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it. Wash the filter materials/ media in a bucket of tank water and re-use the media. Tip the bucket of dirty water on the garden/ lawn. Cleaning the filter means less gunk and cleaner water with fewer pathogens so any medication (if needed) will work more effectively on the fish.

Increase surface turbulence/ aeration to maximise the dissolved oxygen in the water.

Start a new thread in the emergency section of the forum and post clear pictures (and maybe video too) of the fish so we can check them for diseases.
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Old 03-31-2023, 10:47 PM   #5
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When all is said, of course the very quickest way wold be the most humane
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Old 04-12-2023, 04:04 PM   #6
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BTW it has been said that most fish lack the nervous system that would allow them to feel pain .

In the past, I has a community tank that I also placed a small African frog
Long story short..
The frog started to nibble on a few of the small tetras and one even has most of their mouth bitten away.
That fish just continued to swim about normally normally until it finally died. Evidently it felt no pain.
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Old 04-12-2023, 07:21 PM   #7
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IMO, It really boils down to what way you are most comfortable doing. Smashing them is the fastest way but not everybody can handle doing that. Clove oil is another option as is the alcohol but clove oil is not always easy to find. It's been reported that PETA recommends putting the fish in boiling water as a way to euthanize them as the death would be instant. So there are a lot of options that are " humane". So what ever you feel most comfortable doing is the most humane imo.
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dyi, dying, dying fish, fish, sleep

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