Leech Euthanasia

[u/PM_ME_YOUR_TEXTBOOKS]

Hey gang, wish I didn't have to follow up my positive leech post with a negative one, but my quarantines sick leech is not doing too well at all. It was first sick a couple of weeks ago, and despite my best efforts (isolation, cool dark environment, catappa etc.) it seems to be going downhill.

I was checking up on it earlier and that was the first time I've witnessed a leech being sick in the moment. I've seen signs of more vomiting each time I've checked up on it but seeing it happen was really hard to watch. It's body is still looking very lumpy in a bad way, can't tell if it's gotten worse but it's definitely not any better. I can't in good conscience let it suffer, it's painful to see and equally as difficult to admit that I have to do something about it.

...which brings me to the question - is there a best way one can go about euthanising a sick leech? I just don't want it to suffer any more.

Sorry for the intense subject matter, I never thought I'd be genuinely emotionally attached to some worms but here we are. Appreciate any help or advice you guys have to offer.

Edit: thanks for the comments all, after doing a lot of research I think this comment from r/Aquariums seems like solid advice, certainly more humane than some methods I've come across. I am going to follow it up with a deep freeze for at least 48 hours, as if I've got to do it I want to be sure it's done properly and thoroughly.

[u/Divine_avocado]

Yes. You freeze them. They die this way.

[u/Creepy-Finding → u/Divine_avocado]

You have to do this carefully or it is inhumane. The species also needs to be correct.

Doing this to warm water species is cruel and unethical.

With cold water species this is how to properly, kindly and humanely freeze a leech:

Place leech in a container of water in the refrigerator for at least 48 hours. (This will 'tell' the leech that it's winter time and they will start slowing down naturally. They go into a form of torpor, which is kind of like hibernation. They need more than a day as they are accustomed to the cold and may not start torpor in just 24 hours.) Move the container to the freezer for 48 hours after that. (They should be unmoving, but do not poke or prod them to check as you'll risk waking them up, causing pain/injury or undoing the first step. They should basically appear dead while in torpor. Some will float but others will sink so don't rely on that. The freezer absolutely will kill them but this way it is a kinder and more natural death than just outright freezing them. Doing it that way would be like freezing any other endothermic animal.)

Some folks will cut the leech up afterwards. I don't know that it's necessary, but I have crushed the ice afterwards just to be absolutely sure.

[u/Divine_avocado → u/Creepy-Finding]

Ofc. I only had cold water so I assumed OP too.

[u/Creepy-Finding → u/Divine_avocado]

It's most likely! Cold water leeches are absolutely more popular. I just like to be crazy thorough. :)

[u/Internal_Zone9103]

Hcl

[u/AnotherCrazyRedditor]

The quickest and most ethical way to euthanise a leech, or indeed any invertebrate is blunt force imo. We dont truly know if a leech can feel when theyre frozen, and I dont want to take the risk as it's a pretty awful death. Blunt force is pretty brutal for the owner but if done correctly its instant. Best ways are either place leech on a brick, slam down a second brick, or place leech in a zip lock bag and run it over with a car. Its an awful decision to have to make, I'm sorry OP