I’m using i3 with kitty term & fish shell, my editor of choice is micro. I have tried setting the editor in kitty & fish but nothing has stuck, I’ve tried setting it in my bash.rc & even setting it in various other programs. I even downloaded nvim to try that as well but i3 keeps opening mousepad as the editor.
You’re going to have to be more specific - HOW do you invoke your editor in i3, and what do you have that configured to be. You mention you use fish as your terminal shell, which is lovely, but doesn’t tell us HOW you invoke any editor at all. Be precise and you will get an answer in a reply, as this should be trivial.