Mermaid Treasure (Not Quite a Mermaid #5)
When Electra hears of hidden treasure in the caves near Mermaid Island she is very excited.
She and her mer-friends decide to form a treasure hunters club but their first hunt is abandoned when everyone gets stung by purple jellyfish! On the way home Electra finds a tiny rare dwarf seahorse surrounded by the same jellyfish. She swims in and saves him before he gratefully