2.4 out of 5 from 85 votes
Some time ago, the evil Poseidon destroyed the continent of Atlantis and all of its inhabitants - except for two: the green-haired baby Triton, and the mermaid Pipi. Triton was brought by the white dolphin Ruka to the shore of a fishermen's village; and there, he was raised by a kind man for thirteen years. However, the time has come for Triton to learn the truth about his heritage, the death of his parents at the hands of Poseidon, and what he must do henceforth: track down Poseidon and bring peace to the seas again. With the help of Ruka, Pipi and other aquatic friends, Triton sets forth to fulfill his destiny.
In AD 2008, mankind developed deadly weapons and eradicated most of the Earth and its people. 20 years later, a young boy named Conan and his 'grandpa', one of the last survivors of the devastation, live a peaceful life on Remnant Island. One day Conan rescues a girl on the beach named Lana and learns the true nature of the rest of the world. After Lana is kidnapped, Conan's good nature propels him into the biggest adventure of his life: to find Lana, High Harbor, Dr. Lao, and a way to crush the evil and oppressive city of Industria.
While Future Boy Conan and Umi no Triton have a different sort of environment (Umi taking place in the sea, and Future taking place aboard ships and other things), they have a very similar feel. Each main character is an abrasive, rash young man who is thrust in the middle of a scenario he does not enjoy. There's a sense of adventure in both anime, as well as a younger feel.
If you liked one, give the other a try.