The Leatherjacket also known as Leatherjack, Zapatero and Skipjack. They are not poisonous to humans, meaning they cannot kill you if you get pricked by one of their finlets. However, they do have sharp spines on their dorsal and anal fins which can administer a very painful puncture wound to you. Once pricked, your hand and the area it stuck you will feel like it was hit with a hammer.
So if you hook one the best way to remove it from your hook is with a de-hooking tool. It will prevent you from having to touch the fish. Another way anglers get stuck by the Leatherjacket is while cast-netting for bait. The Leatherjackets get into the bait school that you are cast-netting, and as you slide your hand up your net to remove the bait, the Leatherjacket will be mixed in and one of the sharp fins will catch your hand. The painful feeling in your hand usually takes some time to set in and about a day to go away.
Thanks for the great question!
Captain David M Rieumont
The Online Fisherman Inc.