This is the Arctic Grayling Lapel or Tie Tack. The photo is the highlighted version. Both options are available here.
Once native to northern Michigan(near me), but has now gone extinct due to lumbering in the last century, it is still found in a few places within the United States. There are small populations of it out west and you can find it in pretty good abundance in Alaska. There is discussion on bringing it back to to Michigan.
The unusual shaped, colorful dorsal fin is what is the unique feature of this species.
This is the same casting I use for the ‘Fish-On” and “By-The-Tail” pendants. It would make a nice set.
The 3rd option is the fully enamel painted option. See sample photo in gallery of a Arctic Grayling Fish-On Pendant I painted for a customer. Please allow min 2 weeks for a enamel painted version and any gold orders. These are made to order.