Aquarius
What is already familiar, instinctive, and ready to be carried forward.
Pisces
What is arriving, stretching the old shape, and asking for a new response.
A cusp is best understood as a threshold image: Aquarius's air fixed quality meets Pisces's water mutable quality. The Sun is still in one sign at a time, while the neighboring symbolism can describe the season around it.
Aquarius brings
Aquarius is ruled by Saturn and Uranus and speaks through air fixed movement. Its familiar lesson is about the visionary.
Pisces arrives
Pisces is ruled by Jupiter and Neptune and changes the texture toward water mutable expression. Its invitation is to practice the mystic.
A boundary, not a loophole
If you were born near a sign boundary, use an accurate birth time and place when a precise chart matters. The cusp language can be a useful metaphor, but it should not replace the actual Sun sign.