These guys will always be around.
I killed my pet fish.
It was a mercy kill, putting my fish out of her (pretty sure it was a girl) misery. She'd been sick, not eating, puffed up to more than twice her size, and was so bloated her scales stuck out. It was disgusting, and I imagine not comfortable for her. Possibly even painful. So I ended it for her.
Thing is, the other fish in the tank (same species, same sex), might have also been sick because she hadn't eaten in a couple of days. But the morning after I killed her companion she was as lively and hungry as ever. Could it be she hated the other fish and was finally happy to be alone? Could she have recognized what I do to fish that are dying and made a change? Probably neither, but it is a pretty big coincidence.
Because there doesn't seem to be too much information on how to actually kill a pet fish on the internet, I'm going to go through what I read and what I did, so if you don't want to know how people kill their pet fish maybe this just isn't the post for you (but seriously, do you not read titles?).
The internet thinks that the best and most humane way to euthanize a fish is to separate it into another bowl, and mix the water with drops of clove oil. The clove oil puts the fish to sleep, literally. Much like euthanizing animals, it's the overdose that's the lethal part. First, you put just a few drops of oil in to calm the fish and put it into a sleep- it'll go belly up but still be alive (don't mistake the belly up to be death...). Then, once it can't feel anything and isn't stressing, you give it the lethal overdose and in time it dies. It's supposed to take a while, but at least it doesn't feel anything, which is different from freezing it (some fish can survive in cold temperatures, so they're very much alive when they slowly die).
Since it was late on a Friday night and I did not have any clove oil on hand when I noticed my bloated fish was belly up but living, I could not use that method. There are other methods online, which fish enthusiasts use, but none seemed like a quick or sure death (Alka Seltzer being one of them, garbage disposal being another). But I did have other tools on hand, which I figured would be faster and possibly more humane anyway, if only I had the stomach for it. That... that was hard. I know it's only a fish, and I know I've had pets euthanized before due to illness, but being the hand that deliberately killed an animal was new to me.
I set up a plastic cutting board and a steak knife (meant to cut meat but not so sharp as to cut the plastic bag I wanted to use and without ridges) on the counter in the kitchen, next to the sink. I gathered my nerves and made the decision that this was the only option and I was not going to panic or hesitate. I scooped the fish into a plastic bag with just enough water to carry her through the apartment. Back in the kitchen, I emptied most of the water into the sink, sealed the bag, laid it on the cutting board, took a breath, and sliced the head off.
My fish was a platy, and other than being bloated was a very small fish. I don't know if it would have been as easy on other species, certainly not larger fish, but this fish was big enough to get a grip on but small enough to be easily decapitated by a steak knife. Once it was over, and it was very clear she was out of any pain or suffering she might have experienced, I felt relieved. I took out the trash, cleaned my tools, and put them in the dishwasher (for good measure).
I didn't hesitate and it was all over within a minute from plastic bag to death, so the suffering at my hand was very minimal. And I felt good that I'd been able to take control and speed nature along when possible pain was being felt. But afterwards I couldn't just go to bed. I stayed up late surfing the happiest parts of Reddit to make myself feel better, or at least flood my mind with cuteness so I wouldn't go to bed with the image of my fish fresh in my mind. It helped- at least to the point that I didn't have a nightmare.
I'm really hoping I won't have to do that again, though. The other fish is doing really well- swimming enthusiastically, eating voraciously, picking on the snails, pretty much being a happy fish. Which is good. I'm a little nervous she won't survive the move, whenever that ends up happening, but at least I'm a little more prepared now.