A WOMAN has taken her obsession with mermaids so far that she swims in a tail - and believes that she is a real-life mermaid. Cassia ‘Sia’ Shells lives in Toronto, Canada with her fiancé Adrian. Her love for the mythical sea creatures since childhood, where she collected mermaid dolls. The 29-year-old says she relates to mermaids on a personal level, and in fact she believes that she is a mermaid herself.