is it any good fishing in the fall or winter at the dam? And while I was there today I had someone tell me that a few years back a guy caught a flathead out of shenango lake that was 15 oz from the state record. I didn't think there were flats in the lake or dam. Is there or was he full of it

do you have many other options when the lakes are frozen :p... ive caught some walleye there and catfish...nothing big but know some other guys that fish it alot. is not the easiest place to fish but  fish dump out of the lake and holding up there

From my experiences it doesn't fish as good as it does in the spring and summer, but yeah it's all right.  You'll get eyes, trout, and all the other usual stuff thrown in there.  I haven't had much luck there in the winter. 
 
As far as flatheads, yeah they are in the river above the lake, the lake, and the river below the lake.  I haven't caught any, but I know for sure they are there.

Oh cool. I didn't think there was any flats in there. Good to know

Shenango has flatheads throughout it's waters. The lake should have some monsters swimming in it. This 25lber. came out out the lower river a few years back. I was Walleye fishing and landed it on 6lb. line. It was released shortly after this photo. 

That's a nice fish.