I had to euthanize a few sick fish yesterday and looked all over the web to see what the standard practices were. I have to say some of them seemed pretty mean. I know as a kid my mom would flush them down the toilet but that was long before we realized the damage it could do to the local watershed (besides being a not so nice way to die either).
While reading I came across two options that I considered viable. One was to use clove oil to knock the fish out then add vodka to kill it (or kill it any way you want WHILE it is unconscious).
The other was the use of MS-222 (AKA tricaine, Ethyl 3-aminobenzoate methanesulfonate salt, Tricaine Methanesulfonate). I am probably about to be labeled the enemy for saying this, but I have used it in laboratory research before. I was unable to find any clove oil at my local pharmacies (I wanted to try this technique and avoid asking for anesthesia) so I called my old boss up and got some MS-222.
I noticed in reading on the web that people recommended sprinkling it into the container the fish was in - or even the isolation tank. And no one mentioned buffering the pH. This is the main reason I am writing. I know people think that those of us who have done research with animals are cruel people but most of us do everything we can to minimize both the number of animals and the amount of suffering (just for the record my research is trying to cure diseases like cancer and cystic fibrosis, not sell makeup). MS-222 is a highly acidic compound, and should NOT be used without buffering the pH. Since the amount of buffer needed is dependent not only on the initial pH of the water, and the acidity of the compound but also upon the other compounds (chemicals) in the water I can not tell you put this much MS-222 and this much sodium bicarbonate (baking soda) into the water. I also would strongly recommend not putting this stuff into a tank - even an isolation tank. It is carcinogenic and low level chronic exposure can not be good for fish (especially the next batch of sick ones that goes into the isolation tank).
First things first use gloves while handling this compound - you don't want cancer. Use a fairly small container (big enough not to freak the fish out), put in the MS-222. I would use about a table spoon (use disposable containers and plastic ware to measure and store this stuff - toxic) per quart of water. Then measure the pH (strips would be good for this application). pH it with sodium bicarbonate until it is a bit above 7 - like 7.4. You want to pass neutral and go a bit basic in case the fish requires more MS-222 to overdose it - like my angel fish did last night. Then introduce the fish. The compound can be reused if stored in an airtight container its good for about a year and a half or so, it will darken, but it will still work.
To give you an idea what to expect I will tell you about last night. They will swim a little, then pass out and lay on the bottom. Different species take different levels to overdose as well as different times to onset of effect. I had three fish in my isolation tank all started being sick in different ways (not a water quality issue - a too impatient to quarantine incomers issue), all had progressively gotten worse despite treatment. One was a molly who was very sensitive to the anesthesia. She was in for a second and went straight belly up. The large angel fish took about 10 seconds to pass out, but still had gill movement indicating he was still alive (until I added more to overdose him). Surprisingly as if to prove species and not size was the difference the little zebra fish stayed conscious the longest - just swimming around checking the container out.
In the research industry there is a lot of emphasis on secondary form of euthanasia. You do not want the animal to wake up and be in pain. If you euthanize a fish with either ms-222 or clove oil and vodka you should likely confirm death. This can be done by rigor (let the fish stay in the solution overnight until the body as has hard as a wood board) or by performing a secondary like decapitation. Again, please do not flush the body down the toilet. Putting it in household trash is much better than that. Anyway. I hope that this helps if anyone of you ever has to do this. Its not fun, but it seems more humane than letting them suffer to death. As to disposing of the MS-222 I don't know what the best way is. I suspect that pouring it on the ground outside is better than down the sink, but I don't know. I plan to take it back to the lab and let them dispose of it properly.
While reading I came across two options that I considered viable. One was to use clove oil to knock the fish out then add vodka to kill it (or kill it any way you want WHILE it is unconscious).
The other was the use of MS-222 (AKA tricaine, Ethyl 3-aminobenzoate methanesulfonate salt, Tricaine Methanesulfonate). I am probably about to be labeled the enemy for saying this, but I have used it in laboratory research before. I was unable to find any clove oil at my local pharmacies (I wanted to try this technique and avoid asking for anesthesia) so I called my old boss up and got some MS-222.
I noticed in reading on the web that people recommended sprinkling it into the container the fish was in - or even the isolation tank. And no one mentioned buffering the pH. This is the main reason I am writing. I know people think that those of us who have done research with animals are cruel people but most of us do everything we can to minimize both the number of animals and the amount of suffering (just for the record my research is trying to cure diseases like cancer and cystic fibrosis, not sell makeup). MS-222 is a highly acidic compound, and should NOT be used without buffering the pH. Since the amount of buffer needed is dependent not only on the initial pH of the water, and the acidity of the compound but also upon the other compounds (chemicals) in the water I can not tell you put this much MS-222 and this much sodium bicarbonate (baking soda) into the water. I also would strongly recommend not putting this stuff into a tank - even an isolation tank. It is carcinogenic and low level chronic exposure can not be good for fish (especially the next batch of sick ones that goes into the isolation tank).
First things first use gloves while handling this compound - you don't want cancer. Use a fairly small container (big enough not to freak the fish out), put in the MS-222. I would use about a table spoon (use disposable containers and plastic ware to measure and store this stuff - toxic) per quart of water. Then measure the pH (strips would be good for this application). pH it with sodium bicarbonate until it is a bit above 7 - like 7.4. You want to pass neutral and go a bit basic in case the fish requires more MS-222 to overdose it - like my angel fish did last night. Then introduce the fish. The compound can be reused if stored in an airtight container its good for about a year and a half or so, it will darken, but it will still work.
To give you an idea what to expect I will tell you about last night. They will swim a little, then pass out and lay on the bottom. Different species take different levels to overdose as well as different times to onset of effect. I had three fish in my isolation tank all started being sick in different ways (not a water quality issue - a too impatient to quarantine incomers issue), all had progressively gotten worse despite treatment. One was a molly who was very sensitive to the anesthesia. She was in for a second and went straight belly up. The large angel fish took about 10 seconds to pass out, but still had gill movement indicating he was still alive (until I added more to overdose him). Surprisingly as if to prove species and not size was the difference the little zebra fish stayed conscious the longest - just swimming around checking the container out.
In the research industry there is a lot of emphasis on secondary form of euthanasia. You do not want the animal to wake up and be in pain. If you euthanize a fish with either ms-222 or clove oil and vodka you should likely confirm death. This can be done by rigor (let the fish stay in the solution overnight until the body as has hard as a wood board) or by performing a secondary like decapitation. Again, please do not flush the body down the toilet. Putting it in household trash is much better than that. Anyway. I hope that this helps if anyone of you ever has to do this. Its not fun, but it seems more humane than letting them suffer to death. As to disposing of the MS-222 I don't know what the best way is. I suspect that pouring it on the ground outside is better than down the sink, but I don't know. I plan to take it back to the lab and let them dispose of it properly.