What kind of fish is this?

What kind of fish is on the wall in this photograph?

I’ve temporarily labeled it a Blue Marlin, but the dorsal fin is bigger than what I see in other photos of Blue Marlins.

Sailfish Istiophorus platypterus.

could be a blue marlin also… what color was it?

It is a sailfish.

A marlin has a much smaller dorsal fin.

Not to be mean, but…from the caption of the original photo (bolding mine):

Yes, mnemosyne. Based on Desmostylus’s answer, I changed the caption on the photo from “Blue Marlin” to “Sailfish”.