Shovelers Sink, Cross Plains, Dane County
I've been out there as well. It's got a nice spring feeding it, but as I recall it was very weed choked by mid summer, and appeared pretty uniformly shallow.
You never know, unless you go, as they say. My guess would be bullheads and various minnow species can survive, but everything else gets frozen out.
I put the canoe in, and waded for helgies, at the Odana golf course pond on the beltline, once upon a time. All the bullheads up to 5" you wanted, plus various minnow species. Very few helgies, due to the fish presence.