yes that is a sheepshead. After a while they start to take on a yellowish tint. That means that they are going down hill. In that picture I think that I am starting to see a small amount of yellow on that fungus. I would look at that fungus to make sure that it isn't too old and then I would make sure to remove the yellow sections from it.
I got another today too, great find and congrats on your 1st, now you are hooked. I put mine in salt water for at least an hour to supposedly kill the bugs and stuff, I rinse and either cook or freeze at that point.