euthanize fish?

[Xtasia]

yipes.... you guys are cold..

I've done some research on this topic myself and have not come up with an answer yet....

I heard that flushing them live is cruel coz they live for a while and struggle in pollution, chemicals and cold cold water.

Some fish have survived being frozen and thawed... so I didn't like that.

Suggestions to slam the fish against a wall in a ziplock (this sounds cruel)

cutting off their head with a sharp knife... (quick and painless but not something I can do. too much death on my part.)