If you aren't interested in the fish that were already present, have you considered starting over from scratch? The WE and SMB might be better off if there weren't any LMB at all. As an example of how effective LMB are as a predator, when they were introduced into Japan they began terrorizing the snakehead fish there. So sure you might catch a unique fish here and there, but LMB will sit dominantly at the top of the food chain. The presence of an ultra-dominant predator doesn't seem to fit with your goal of having variety. Especially if the dominant fish is one that doesn't interest you.
