How about a simple mod that acts similar to the early released of Craftstore, but one that show's you which fish you've caught in each zone/watertype. The in game achievements list flat out sucks, as it doesn't who which come from what type of water, so it's another one of those things where you have to keep notes outside the game... or keep checking a secondary source.
There's a great source with the info compiled here:
http://www.slideshare.net/NikolTesla...ndium-36911855
The guy who did it is just a great time saver, but it'd be even better as a Craftstore type mod.