The Land Before Time IX: Journey to Big Water (2002)

When heavy rains create a mysterious “new water”, Littlefoot sets off to explore the Great Valley and quickly becomes friends with Mo, a fun-loving dolphin-like creature, who has been isolated from his pod by the weather. When Littlefoot and friends get separated from their parents because of an Earthshake, they help Mo get back home to the Big Water, while avoiding a hungry “Sharptooth Swimmer”.