Why is Pisces always at the bottom of the twelve constellations?

It depends on the time when the constellation "ecliptic 12" appears in the starry sky.

Fish Palace: Zodiac, with symbols. The longitude of the zodiac ranges from 330 to 360, originally from Pisces, hence the name. Due to precession, it has been moved to Aquarius. The sun comes to this palace around February 19 every year, when the solar term is rain.

Pisces: One of the zodiac signs, with the center at 0: 40 right ascension and declination 10. Between the fairy, Aries, whales, flying horses and other constellations. The vernal equinox is near its southern border. Eight stars in the constellation are brighter than four, and the rest are dark stars.