Pisces ends the year, mutable and water — the last sign before the equinox resets the circle at 0° Aries.
Jupiter ruled it before Neptune's discovery in 1846. The traditional attributions of permeability and difficulty holding an edge are the structural position: this is where the twelve-fold division dissolves and begins again.
A chart's very last degree, 29°59' Pisces, is adjacent to its very first. The zodiac is a circle, and Pisces is where that becomes obvious.
Traditionally attributed
Permeability, imagination, sympathy, and trouble holding an edge.
Listed because it is what the tradition says, not because this site can check it. Everything above this line is geometry; everything in it is convention.