Juvenile Kingfish vs. Spanish Mackerel Easy ID Oct 26, 2010 13:43:12 GMT -5 Quote Select PostDeselect PostLink to PostMemberGive GiftBack to Top Post by snookmook on Oct 26, 2010 13:43:12 GMT -5 Jim Plastic called in to The Reel Animals radio show on Sunday and asked the boys to explain how you tell the difference between a juvi kingfish and Spanish mackerel. Well here you go. forshorefishing.blogs.theledger.com/13211/how-to-identify-juvenile-king-mackerel-and-spanish-mackerel/Besides the lateral line difference another way to tell is the color of the dorsal fins.