looks like a sculpin of some sort to me 

round goby?

10 hours ago, Turtle135 said:

round goby?

Correct======aka smallmouth gumdrops. I was amazed to see how many of them were everywhere shallow and deep in the great lakes. This one  from Erie

that one is bigger than I expected, I've never seen one live, is that a typical sized specimen?

I have snagged a few that size, but I believe the average size runs  smaller.

2 hours ago, Catch 22 said:

Correct======aka smallmouth gumdrops. I was amazed to see how many of them were everywhere shallow and deep in the great lakes. This one  from Erie

I believe I've heard estimates of 1 goby for every square yard of bottom.

The main visual difference between the goby and a sculpin is the goby has a black spot on it's dorsal fin. I'm not sure I see the spot in your picture. Deepwater sculpin are native to the great lakes and goby's are invasive. They both feed on zebra mussels and fish eggs. Goby's reproduce 3-4 times per year where I believe sculpins do not