Do fairies have tails? When there's no definite answer, there can be many possibilities of answers. Which means, Fairy Tail will have endless adventures happening to then. That's why, Fairy Tail is created.
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