I’m a bit confused. Your terminal is not Fish. Fish is a shell like Bash, which interprets the commands. Terminal is the window application. Based on the linked image, I assume you have Kitty as your terminal? And you want to open a terminal within your editor using shortcut Ctrl-e?
If so, then I don’t know about this. I thought you want to run a terminal with micro as the editor from outside of micro, not after you started micro. I might have completely missed your point here then.