A Siren isn't really a sea monster but sailors have told tales of these beautiful women that sing to you and seduce you into their trap of bloodlust. They are said to eat the sailors alive or drowned them deep in the ocean.
The water signs (Cancer, Scorpio, Pisces) are passive and receptive. They release their energy cautiously. Water signs enhance empathy and the ability to feel deeply. Pisces illustration by Linda and Roger Garland.