I need to euthanise some fish and I live in Australia. Websites are useful too
I found mine at a pharmacy, it's used as a toothache remedy.
I found mine in a well stocked grocery store in the pharmacy section near the cold remedies and first aid supplies.
I'm sorry you've had to make this difficult decision. I also found mine at a pharmacy. I had to ask for it. They kept it behind the counter. Call first.
Our drugstores don't carry it here anymore. I had to go to a health food store to get it.