A bit late for the party but here is your answer: fish pedicure has good benefits on, it comes with minor risks also.
For those who do not know what fish pedicure is:
A fish pedicure, also known as a fish spa, involves patrons dipping
their feet in a tub of water filled with small fish called Garra rufa.
Garra rufa are sometimes referred to as “doctor fish” because they eat
away dead skin found on peoples’ feet, leaving newer skin exposed.
Lancet in 1989 mentioned one unusual alternative treatment for Psoriasis which is so-called ‘Doctorfish of Kangal’. These fish feed on the skin scales of bathers, reportedly reducing illnesses such as psoriasis and atopic dermatitis.
It seems also that a spa in Turkey has been offering a fish pedicure service for more than 100 years, to treat serious skin conditions in 3,000 patients every year, such as psoriasis and eczema. In 1988 it seems that it became an official treatment center for people who have psoriasis.
But fish pedicure could transfer bacteria and diseases to you.
The CDC has published a report by U.K.’s Centre for Environment, Fisheries & Aquaculture Science, which investigated the types of bacteria associated with fish pedicure. Results showed that those fish carried strains of several bacteria that could cause soft tissue infections for people with open sores, skin cuts, underlying medical conditions such as diabetes, AIDS, cancer, or advanced age.
See:
Warwick D, Warwick J. The doctor fish—a cure for psoriasis? Lancet.
1989;335:1093–4.