An expected thing is that fish have souls to collect. They live and die in the game, implying a soul should exist as with any other life->death entity.
However, when fishing the dead fish nearby grant no souls.
I'm thinking the 'stopkicking' functions for both the fish + eels should have an event fired that the thing "died" to make it easier for the souls to spawn.
This would make it not need to have checks for fishing events to determine if it was actually a fish brought up and not a trinket or pouch/etc.
Fish at a fishing hole as Wortox and see that the fish brought up give no souls.