E. J. Altbacker

Everywhere Gray and Barkley swim, fish are whispering of a growing threat, of a shark named Finnivus who will eat anything or anyone, and won't stop until he has seized control of the entire ocean. Finnivus has an armada of vicious battle sharks to help him expand his empire, and Gray realizes that it's up to him to save the Big Blue. But first he must train with Takiza, the wise and mysterious fighting fish who has promised to teach his young apprentice...

With the ocean on the brink of chaos, a young shark Gray and his best friend Barkley, exiled from the safety of their peaceful reef home, will have to battle ferocious shivers, or join them, to survive.

"The Justice League Dark emerges from years of hiding to fight the villainous force stalking supernatural heroes and villains alike! John Stewart and his band of abandoned Green Lanterns must hold the line against an invasion of murderous zealots in an uncharted dark sector after their rings have stopped working! Barry Allen battles for the soul of his former Flash partner, Wally West! And Jackson Hyde and Andy Curry, son of Black Manta and daughter...

"As the first Shark Wars series arc draws to a close, hero Gray unexpectedly finds himself the ruler of the ocean. He's got to make wise decisions in a time of upheaval and isn't sure if he's up to the task! Dangerous prehistores are loose in the Big Blue, and Gray must defeat their evil leader, Grimkahn. But if he is to do that, he and Barkley must first outsmart the sneaky and dangerous frilled shark, Hokuu..."--Publisher's website.