A US spa owner in the town of Gilbert, Arizona, believes she has a constitutional right to use garra rufa fish – carp fish with no teeth – to nibble dead skin of customers’ feet.

The Arizona Board of Cosmetology is legally entitled to stop Cindy Vong, owner of LaVie Nails & Spa salon, from using the fish in her spa due to issues of consumer protection – according to the latest ruling by a state court of appeal. The problem is that this ruling meant no alternative form of regulation was put in place – instead the practice was banned outright, which threatens Vong's business' right to exist.

Donna Aune, executive director of the Board of Cosmetology, said the fish, by their nature, foul the water in which customers place their feet – leading to possible infection, according to the eastvalleytribune.com.

Vong set up Spa Fish in 2008 a separate arm of LaVie, however in 2009 the Board of Cosmetology sent her a letter detailing the rules for disinfection and storage of pedicure equipment.

“Any tool or equipment used in a pedicure must be stored in a dry storage facility and disinfected in a very specific way,” the Board’s then director Sue Samson wrote to Vong. “It is impossible to disinfect the fish coming in contact with your clients’ skin in the required manner. You are jeopardising your clients’ health by performing this type of pedicure.”

Despite a 2011 report published by the UK Health Protection Agency saying that the risk of infection from using these fish in spas is “very low” – and confirmation by the US Centers for Disease Control – Aune dismissed these findings.

US Attorney Clint Bolick said the only path left for Vong is to take the case to the US Supreme Court because, if left undisturbed, the ruling allows state officials to ban an entire business practice. While the appellate court said the Board of Cosmetology was acting within its power to protect public health, the rules did not put Vong out of business as she can still perform other procedures at the salon. Bolick believes, however, that banning the fish spa practice requires greater justification.

According to Bolick, the precedents that would be set here could determine the future of businesses like Uber, which use technology to provide alternatives to taxi services. While states can impose necessary regulations, Bolick believes they cannot set up barriers that completely ban such services.

“The issue is really a business’ right to exist,” said Bolick.