Fisherman's Hope : The Seafort Saga, Book 4 (Unabridged‪)‬

Nick Seafort returned to Earth expecting a court-martial, but instead he's tapped by the naval academy. This is no ordinary desk job.... Luck has always run in both directions for Naval Commandant Nicholas Seafort. While he has managed to save the Hope Nation colony from alien attack, he and his friends have paid a heavy price. Most recently his exploits have earned him a dignified position as an instructor at the United Nations Naval Academy. But as Seafort suspects, trouble isn't far behind. A return to Earth means a return to his roots, some of which he wishes would remain buried. He's uncomfortable with fame and can't always restrain his temper as the political machine shifts around him. But when the fishlike aliens mount an attack, Seafort is the only man Earth can count on. Now he must decide whether he has the courage and fortitude to make a terrible choice....