It is not known to evolve into or from any other Pokémon. It can only be obtained by breeding Manaphy or another Phione with Ditto.
Phione was considered by some to be a legendary Pokémon. However, due to the fact that it can breed and multiple individuals can be obtained, its legendary status remained disputed, with contradiction occuring even between official sources. In Pokémon Ranger: Guardian Signs, however, it is not referred to by the game as "rare" or "legendary", which is the case for all other legendary Pokémon in the game, thereby proving its lack of legendary status once and for all.
Phione is the result of breeding Manaphy in the Generation IV games. As a result, it is very similar to Manaphy in body structure. It has a tiny body with a red gem on it. Phione has a single rudimentary foot spike and club-like arms. Phione's head is larger than the rest of its body, and extending from its eyes are two small purple circles. It has a flotation sac on its head with a single, ribbon-like antenna on it.
Gender differences
Phione is a genderless species.
Special abilities
Phione going in the drain
Phione's abilities are similar to Manaphy's, but weaker. Phione is unable to use a number of attacks that Manaphy is able to learn, most notably: Tail Glow, Heart Swap, Hyper Beam, or Giga Impact. Phione are supposedly able to create a dew that cures all ailments. Phione also has the ability to melt its body into water and change its body into a more liquid state similar to Vaporeon.
Behavior
Like Manaphy, Phione always go back to the spot where they are born.
Habitat
Phione live in warm seas, especially around the Sinnoh region.
Phione, the Sea Drifter Pokémon. Phione lives in warm oceans. It inflates the flotation sac on its head allowing it to float on the waves and look for food.
Phione is the only Pokémon that is obtainable by breeding a legendary Pokémon.
Phione is taller and weighs more than its parent, Manaphy.
Phione can be bred not only from Manaphy, but also from a Phione. However, Phione are unable to produce eggs that will hatch into Manaphy.
Pokémon.com has incorrectly stated that Phione is legendary.[1]
The website initially answered that Phione was not a legendary Pokémon, but it was soon changed to the incorrect answer.
However, this answer was again overturned by a HeartGold and SoulSilver guidebook published by the same company that runs Pokémon.com, where it was stated that Phione is not a legendary due to its ability to reproduce.
This is further evidenced by Pokémon Ranger: Guardian Signs introducing Phione as it would any other wild Pokémon, instead of calling it "rare" or "legendary", as is the case for all legendary Pokémon in the game.
Phione and Nincada are the only Pokémon that can be obtained by breeding a Pokémon they cannot evolve into (as Shedinja is technically a shed shell).
Phione's name is likely a combination of the final syllable of Manaphy's name with clione, sea angels. Clione are remarkably popular in Japanese documentaries, especially in Hokkaido, on which Sinnoh is based (this may also explain their appearance in Chocovine Town). Also, like clione, Phione's name is pronounced in three syllables.