So far as we know, no one has celebrated a Neptunian Birthday, a year on Neptune lasting nearly 165 years.
However, it behoves us to think that some day someone will, and when that happens it will have been predicted here at Every Day Counts.
Maybe it will be you.
Neptune has 14 known moons, the most prominent one being the largest, Triton, which is the only large moon in the Solar System with a retrograde orbit, an orbit in the opposite direction to its planet's rotation. Because of this and its similar composition to Pluto's, Triton is thought to have been captured from the Kuiper belt.