The Pirates of Dark Water (1991)

When Ren, a young son of a lighthouse keeper, rescues a stranger foundering in the rocks near his home, he learns the man was an aide to his true father, a great king. Ren is given a magic compass crystal that guides him to a dragon who shows him that the only way to claim his heritage is to find the Thirteen Treasures of Rule. Unfortunately, a pirate ship captained by the evil Bloth is also aware of this treasure and is relentlessly pursuing Ren for it. On his side, Ren soon acquires companions like Ioz the Pirate, Tula the Eco-Mage and Nibbler the Monkey Bird who help him in his quest. That quest becomes all the more urgent when Ren learns that the Dark Water, a carnivorous form of water that consumes anything it snares, threatens to envelope and destroy his world and only the treasures he seeks can stop it.