Gargi Desai

A golden turtle teaches a cruel princess a lesson by cursing her, but she learns to be kind and is rewarded.

Two princesses, Aurora and Anna, face jealousy and curses. With the help of witches, they transform into fish and mermaids, leading to a battle and a reward.

This book has a series the name is golden turtle 2

Four fish friends are targeted by jealous fish who try to break their friendship, but a clever dolphin helps them reconcile.