The color and patterns are different on a chain pickerel than they are on a northern pike. On pickerel the pattern looks like a chain as in your picture. Don't know currently, but some state record chain pickerel have come out of the Little Red River. Also chain pickerel are a native fish to Arkansas; pike are not. I'm not sure the placement of the dorsal fin has any bearing. There is a book about fish in Arkansas that is helpful, though much of it is about various kinds of minnows. Got to thinking: is it "pickerel" or "pickeral"?