Gial Ackbar was a Mon Calamari male. During the Clone Wars, he was captain of the Mon Calamari Guard and fought in the battle that secured Prince Lee-Char's way to the throne as King of Mon Cala.

He became the foremost military commander of the Alliance to Restore the Republic, becoming a symbol of defiance against the Galactic Empire's subjugation of non-Humans and attracting major Mon Calamari support for the Rebels, thereby supplying the Mon Calamari star cruisers that made up the majority of the Rebel fleet. From his ship Home One, Ackbar acted as fleet commander during the Battle of Endor, evading the Imperial trap of an unexpectedly operational Death Star II. Lando Calrissian led the starfighters, which eventually destroyed the Death Star from within. Ackbar reacted to the Rebels' triumph with a sigh of relief.

http://starwars.wikia.com/wiki/Gial_Ackbar/Canon

PS ITS A TRAP