No, it is a fictional planet. Not even an asteroid or minor planet has been named after it.
Unless you are thinking of Ganymede a moon of Jupiter.
Mercury is a real planet, it's Pluto that is not a real planet.
Yes, the planet is a real planet and yes, it is composed -- apparently -- of the real mineral diamond.
No, it is not real planet because Akira Toriyama, creator of Dragon Ball, created the name of the fictional planet. It never exist in our real life universe.
No. Such a planet could not exist.
There were a real live alien on planet?
No it was not real.
No where, it is not real.
no
no
No.
no
Yes. It's the 5th planet from the sun.