I feel obliged to post the below for fellow shrimpers that might be interested on how to humanely put down shrimp, without needing to resort to ethically questionable methods:

Because invertebrates  do not have the same metabolisms than humans or other mammals, rapid cooling is a very kind way of drifting off your shrimp gently into oblivion with the addition of ethanol as anaesthetic. There is the right way and a wrong way of doing it. Ethanol is a veterinary acceptable anaesthetic.

Crush some ice in a bowl. Put vodka in a 1ml syringe. Put the shrimp in a breather bag with a relatively small amount of tank water and a small sprig of moss. Once the affected shrimp is in the breather bag, slowly add the vodka from the syringe to the bag with the shrimp in. By adding the vodka first, the shrimp is not shocked with temperature change. Add the crushed ice to the bag with a spoon until it forms a slurry- that means enough liquid water should be present so that the shrimp does not get distressed. It works quickly without causing distress. I put the breather bag in the freezer afterwards to ensure that I have euthanised the shrimp effectively.

There are a few articles available when you Google search. If you want a link, please see below veterinary guide:

https://www.avma.org/KB/Policies/Documents/euthanasia.pdf

@KeenShrimp hopefully not needed however very helpful and interesting info. The link provided is full of useful info, thanks.

Myself, over the fifty odd years of fish keeping, have used varying methods with a more recent use of API PIMAFIX slowly providing an overdose drop by drop, no noted stress. Haven't needed to use anything for over 18months thank goodness.

I am such a softy, even the thought upsets me :'( But I must thank you as I had no idea how to go about this ( hopefully I never have to use it ), Good info on a hard to talk about topic ! :)