This is an old thread, but you never know what might be useful...
I grew up in Ft Wayne and in Steuben County to the north, and there is more excellent fishing there than one would think, and very few private lakes. Clear Lake (east of Fremont) was once the premier fishing lake in NE Indiana, and that's saying a lot. with about 3000 acres of crystal clear water, gravel bottom, huge shallow flats and holes approaching 100 feet, there's no limit to what you might want to fish for successfully. At one time, Clear Lake held the state record for Walleye, Northern, and Rainbow Trout at the same time.
The Lake James chain is another gold mine for fishing, with my personal favorite being Snow Lake. Once upon a time it wasn't uncommon to hear of 16"+ crappie being hauled through the ice. Not sure what has happened there lately.
Chekc any map of the area; even the smaller, lesser known lakes have their value. There's a little pond called Mirror Lake east of Clear lake that has public access for a non-motorized boat (it's so small you can row across it in a matter of 5 minutes or less without breaking a sweat), and I've caught numerous 4 Lb LM bass and many bull gills and red-ears.
Don't ignore the Fawn River or Pigeon River either. The Fawn was always great for Northern, and the Pigeon for trout.
Take your pick, you can't really go wrong.