update: I tried with all my songs and yes I know it doesn't work with every song. I just think it works if you play the song on time or it works with some sort of upbeat song. But yea, it doesn't work perfectly like you would expect.
Aquarius was pasted down from Lucy's mom. Possibly when Lucy was younger she would play with her moms celestial spirits.This is the saddest and sweetest, cause anyone who watched fairy tail would know how deeply Aquarius cared for Lucy