I have felt that the best way to euthanize a large fish is a baton-blow to the head. That is too hard for most people.
The other two methods include placing the fish in a freezer In a suitable size container that prevents the fish from being terrified. Hypothermia sets in slowly and the fish perishes painlessly. (They have no spinothalamic tract and they are unconscious by the time freezing occurs.)
I think that would be a very large container to fit into your freezer.
The third method involves oil of cloves, that is available anywhere they sell essential oil‘s such as General Nutrition Co GNC. You simply put a few drops of water per gallon into a ziploc or jar, shake the container very well (I’m thinking Ziploc bag) then pour the emulsified oil of cloves and water into a container with the fish in it. The oil of cloves anesthetizes the fish at which point you can slide it into the freezer without the water. No fear.
Enter your email address for a free PDF of this article including its images.Enter your Email Address
My Favorite Amazon Recommendations
Items and content will not show in "Reader View" check your browser.
PraziPro for Flukes
Buy Some Good Koi?
Best Food, Ever
Pro Air 60 Aerator is a VERY high output air pump pushing my whole fish room (17+ drops), and I have one at home driving everything there, and I have one as a back up.
Topical For Koi and Pond Fish Ulcers
Koi Health & Disease
I have over ten of these Titanium Heaters in my fish room and at home. They're a paradigm shift in aquarium heating. They're titanium and 400W for under $30! Whaaaaaaaaat?
CyroPro by Hikari is safe and easy for Anchor Worms and Fish Lice.
Whatever heaters you use, back yourself up with a temperature controller, it'll turn on, and off your heaters. If your heater seizes "on" at least the thermostat will stop a tragedy.
LifeGuard by Tetra is a tablet version of a tame 'chloramine-t' or 'halamid' compound that's easy to get and good on bacterial infections, in baths.
For me, filtration-of-choice
Rubber sided, round, nettable tanks
1200 Watt heater, on a thermostat held securely above the waterline, works GREAT as a large tank heater. That's all I'll say because there's risk of electrocution and all that. But then, even in a bucket you could get killed. Sound like fun?
What Does Ajax Eat?