Pisces is ruled by Neptune, and co-ruled by Jupiter. Aquarius is ruled by Uranus and co-ruled by Saturn.
The Age of Pisces was supposed to bring humanity spirituality, compassion, empathy and themes of sacrifice that will lead to spiritual transcendence. Neptune represents dreams, illusions, spirituality, and higher consciousness. Jupiter here rules expansion, religion, metaphysical, and growth. On the downside, when people are devoid of true spirituality, ugly things like deception and the Abrahamic ilk manifests and expands through Jewish dogma.
The transition into the Age of Aquarius will bring progress, innovation, individuality as well as societal and technological advancements and humanitarianism. Saturn in Aquarius here will bring structure, boundaries and responsibility to these advancements. People must learn to be cautious and prudent with these advancements, unless chaos will ensue.