Girls are said to love them but a new swimming device that secures the legs inside a mermaid tail is being carefully watched by safety officials. The toy allows young girls to swim like mermaids and is a growing trend — and safety concern — at pools in Calgary and Edmonton. “My kids’ faces just lit up and they’re like, ‘Holy cow, there’s a real live mermaid in the pool!’ So we picked them up and ordered them and it’s great,” the CBC quotes Calgary mother Sharla Stoffman, who purchased “mermaid fins” online for both her daughters. Stoffman’s eight-year-old Charlott describes the feeling of swimming in the sparkly costume as “free,” while her older sister says it’s just like being a fish. But Calgary lifeguards are making swimmers take the following test before they can wear their toys in a public pool. They must swim 25 metres continuously, tread water for two minutes and swim with confidence while wearing the mermaid fin.