I'm no pro..but I do know this....My Dad's lake is right next to a wetlands conservation area in Illinois, basically a giant marsh that holds a few inches of water year round. There are minnows in it, yes, and in the spring/early summer, the marsh kinda overflows as the fox river does, and some minnows even wash through into dad's pond...so bonus forage. Plus, there are crayfish, and insects that make the 200 yard migration to dad's pond, as well as turtles and waterfowl that are easy on the eyes on a hot summer evening (if you haven't guessed, dad's place is my vacation spot of choice).
Also....frogs. Tons and tons of frogs and toads and salamanders. Bullfrogs, chorus frogs, northern cricket frogs, spring peepers, wood frogs, the list continues. Not a huge amount of them come over to the lake, but enough that a good scum frog is a lure of choice at the right time of year.
As far as i understand it, a bunch of frogs are a good thing (somebody hop in here to correct me) both in providing a protein-rich food base for your fish, but also in helping to keep down your mosquitoes and other biting insects.
Now...for the third time....I'm no pro, and don't pretend to be. I am sure that there is much more to this that i don't understand. But given the opportunity, after seeing the benefits the nearby marsh has to my dad's BOW, I would say yes to putting a marsh near my own pond.
