Frequently Asked Questions About Ichthyotherapy

DESCRIPTION / INTRODUCTION

Ichthyotherapy is the therapeutic use of certain fish (most commonly Garra rufa, the
so-called “doctor fish”) to remove superficial scales and excess keratinized skin. The
practice is best known for its historical use in people with psoriasis at the thermal
springs near Kangal, Türkiye, and it has since been adapted in other treatment settings.
A related but different practice, the fish pedicure or fish spa, uses similar fish primarily
for cosmetic exfoliation of the feet or hands. Although the two practices share a
biological principle, their goals, treatment conditions, duration, supervision, and potential
risks may be quite different.
Scientific evidence for ichthyotherapy is limited. Small studies and clinical observations
suggest possible benefit for psoriasis, but the best-known clinical study combined fish
treatment with ultraviolet A (UVA) therapy, making it difficult to determine how much
benefit came from the fish themselves. At the same time, public-health authorities have
raised legitimate concerns about infection control because the living fish cannot be
disinfected between patients.
These 20 questions explain how ichthyotherapy works, what is known about its
effectiveness and risks, how medical treatment differs from commercial fish spas, and
what concerns arise for both patients and the fish.

At a Glance: Medical Ichthyotherapy and Commercial Fish Spas

	Medical Ichthyotherapy	Commercial Fish Pedicure / Fish Spa
Primary purpose	Treatment of a skin disorder, historically especially psoriasis	Cosmetic exfoliation, relaxation, or novelty
Typical body area	May involve extensive affected skin	Usually feet or hands
Typical duration	Historically much longer treatment sessions and repeated treatments	Usually short sessions
Main fish	Primarily Garra rufa	Often advertised as Garra rufa, although species identification may not always be certain
Medical supervision	Ideally part of a medically supervised treatment program	Usually none
Evidence of medical benefit	Limited evidence, mainly involving psoriasis	Little evidence of medical benefit
Major concern	Infection, patient selection, and limited evidence of efficacy	Infection control, species identification, regulation, and fish welfare
Can the fish be disinfected between users?	No	No
Standard psoriasis treatment?	No. It remains a complementary or investigational approach	No

QUESTIONS

1. What is ichthyotherapy?

Ichthyotherapy is the therapeutic use of fish to remove excess scales and superficial keratinized skin.

The species most closely associated with the treatment is Garra rufa, a small freshwater fish native to parts of the Middle East. The fish uses its specialized mouth to graze and scrape material from surfaces. When people immerse affected skin in water containing these fish, the fish may remove loose scales from the outermost layer of skin.

The term ichthyotherapy comes from the Greek ichthys, meaning “fish.”

The term was proposed for this therapeutic practice in the modern medical literature in keeping with names for other forms of biotherapy, such as hirudotherapy and maggot therapy. (Grassberger & Hoch, 2006; Grassberger & Sherman, 2013)

Ichthyotherapy should be distinguished from a commercial fish pedicure, in which fish are used mainly for cosmetic exfoliation rather than treatment of a diagnosed medical condition.

2. Which fish are used, and why are they called “doctor fish”?

The species used most often is Garra rufa, a small member of the carp and minnow family, Cyprinidae.

The fish naturally lives in freshwater systems of the Middle East and normally feeds on material such as algae, microorganisms, detritus, and other food scraped from surfaces. Its mouth contains structures adapted for attachment and scraping rather than the type of biting teeth found in many other animals. (Grassberger & Sherman, 2013; Yilmaz et al., 2025)

At the thermal springs near Kangal, Türkiye, G. rufa became famous because the fish graze on the abundant scales of people with psoriasis and other hyperkeratotic skin disorders.

Another cyprinid, Cyprinion macrostomus, has also historically been reported in the Kangal pools. However, Garra rufa is the species most strongly associated with modern ichthyotherapy.

The popular name “doctor fish” reflects their therapeutic reputation; it does not imply that the fish diagnose disease or deliver a known medication.

Correct species identification matters. Public-health authorities have warned that other fish have sometimes been substituted for G. rufa in commercial fish spas. Some substitute species may have different mouth structures and may be more capable of injuring skin. (Centers for Disease Control and Prevention, 2024)

3. How does ichthyotherapy work?

The clearest mechanism is mechanical exfoliation.

The fish repeatedly graze on loose scales and superficial keratinized material. In psoriasis and other conditions that produce excessive scaling, this may rapidly reduce the visible layer of scales.

Removing scales could have several effects:

• making the skin feel smoother;
• reducing the thickness of superficial plaques;
• exposing underlying skin;
• improving penetration of topical treatments; and
• potentially allowing ultraviolet treatment to reach affected skin more efficiently.

However, it is important not to overstate what is known.

The visible removal of scales is well established. Whether other biological effects occur—such as changes in inflammation, immune signaling, or skin chemistry—has not been adequately established.

Ichthyotherapy should therefore be understood primarily as a biological form of controlled surface exfoliation, with other proposed mechanisms remaining uncertain. (Grassberger & Sherman, 2013)

4. What skin conditions have been treated with ichthyotherapy?

The condition with the strongest historical and published evidence is psoriasis, particularly chronic plaque psoriasis.

Ichthyotherapy has also been discussed or used for:

• ichthyosis and other disorders involving excessive scaling;
• atopic dermatitis or eczema;
• calluses and thickened skin;
• rough skin; and
• cosmetic exfoliation.

However, use does not equal proven effectiveness.

Most clinical evidence concerns psoriasis. Evidence for eczema, ichthyosis, or other disorders is considerably more limited, and commercial claims frequently extend beyond what has actually been demonstrated scientifically.

People with inflammatory or infectious skin disease should also remember that disruption of the skin barrier may increase susceptibility to infection.

5. What does the scientific evidence say about effectiveness?

The evidence is suggestive but limited.

The most frequently cited modern study was published by Grassberger and Hoch in 2006. It evaluated 67 patients with moderate-to-severe plaque psoriasis who underwent a three-week treatment program combining daily ichthyotherapy with short courses of UVA exposure.

The average Psoriasis Area and Severity Index, or PASI, fell substantially. About 46% of patients achieved at least a 75% reduction in PASI, and 91% achieved at least a 50% reduction. Patients also reported relatively long periods of improvement. (Grassberger & Hoch, 2006)

Those results are encouraging—but the study has important limitations.

It was:

• retrospective;
• relatively small;
• not randomized;
• not placebo-controlled; and
• based on combined ichthyotherapy and UVA treatment.

Therefore, the study cannot determine how much improvement resulted from the fish, how much resulted from UVA exposure, or whether additional factors contributed.

A later dermatologic review concluded that the evidence remains limited and that additional studies are needed to determine both benefits and risks. (Shih et al., 2020)

Ichthyotherapy should therefore not be presented as an established replacement for evidence-based psoriasis treatment.

6. What does a typical session involve?

The answer depends greatly on whether the setting is medical or cosmetic.

In a commercial fish spa, a person usually places the feet or hands into a tank containing fish for approximately 15-30 minutes.

Historical and medical ichthyotherapy programs have been quite different.

In the 2006 psoriasis study, for example, patients underwent approximately two hours of fish exposure each day for three weeks, combined with short UVA treatments. (Grassberger & Hoch, 2006)

At Kangal, historical treatment regimens have sometimes involved even more prolonged immersion.

During exposure, the fish congregate around areas of scaling and repeatedly graze the skin surface.

This difference in treatment intensity is one reason that the results of medical ichthyotherapy studies should not automatically be applied to a 15-minute commercial fish pedicure.

7. Does ichthyotherapy hurt?

Most people describe the sensation as tickling, tingling, vibrating, or lightly scraping rather than painful.

Garra rufa does not have the type of external cutting teeth that would normally produce a conventional bite. Instead, its mouth is adapted for attachment and scraping.

However, saying that the fish “only eat dead skin and never affect healthy skin” is too absolute.

Repeated contact can irritate the skin, and minor trauma is possible. Rare reports following fish-spa exposure include nail abnormalities and skin infections. (Lipner, 2018; Shih et al., 2020)

Any sensation of pain, bleeding, significant burning, or visible injury should therefore not be regarded as a normal or desirable part of treatment.

8. Is ichthyotherapy safe?

The main concern is infection.

The central problem is unusual: the therapeutic agent itself is a living animal.

A conventional pedicure instrument can be cleaned or sterilized between clients. A living fish cannot.

The same fish may therefore contact the skin of multiple people while living in the same aquatic environment.

Potential microorganisms may come from:

• another customer;
• the fish;
• the water;
• the tank or filtration system; or
• the broader aquatic environment.

Documented bacteria associated with fish-spa environments include organisms capable of causing human infection. Public-health investigations have identified pathogens in populations of Garra rufa, and clinical reports have described infections following fish pedicures. (Centers for Disease Control and Prevention, 2012; Shih et al., 2020)

For a healthy person with intact skin, the absolute risk of serious infection appears to be low, but it is not zero.

Risk becomes substantially more concerning when the normal skin barrier or immune defenses are impaired.

9. Who should avoid ichthyotherapy or fish spas?

People at increased risk of infection should generally avoid fish-spa exposure unless a clinician familiar with their condition specifically advises otherwise.

Particular concern applies to people with:

• open cuts or wounds;
• active skin infection;
• significant skin breakdown;
• diabetes with impaired circulation or sensation;
• peripheral vascular disease;
• impaired immunity;
• immunosuppressive medications;
• severe chronic illness affecting infection resistance; or
• other conditions that impair wound healing.

Patients receiving biologic or other immunosuppressive treatments for psoriasis may themselves be at higher risk of infection and should be particularly cautious.

The draft also mentions pregnancy. Pregnancy itself has not been established as a specific contraindication to Garra rufa exposure. I would therefore remove pregnancy from the contraindication list unless there is another individual medical reason for concern.

10. How hygienic are fish spas, and why have some places banned them?

The major difficulty is that ordinary salon sanitation procedures do not work well with living fish.

The CDC identifies several reasons some U.S. jurisdictions prohibit fish pedicures:

• the fish themselves cannot be disinfected between customers;
• tanks cannot be cleaned using the same procedures used for conventional pedicure equipment while the living fish remain inside;
• the same fish may be used with many customers;
• other fish species may sometimes be substituted for Garra rufa;
• regulations governing pedicures and salon equipment may not accommodate living animals; and
• concerns exist about fish welfare and environmental release. (Centers for Disease Control and Prevention, 2024)

Therefore, a facility can reduce microbial risk through filtration, water management, health screening, exclusion of customers with wounds, and careful fish husbandry—but it cannot create the equivalent of a sterile instrument between customers.

Regulation varies by jurisdiction, so availability in one state or country does not imply legality elsewhere.

11. What side effects or complications have been reported?

Most people experience no major complication, but both infectious and noninfectious problems have been reported.

Published infections following fish pedicures have included:

• Staphylococcus aureus infection;
• methicillin-resistant S. aureus (MRSA);
• Mycobacterium marinum infection; and
• other aquatic or skin-associated bacterial infections. (Veraldi et al., 2014; Vanhooteghem et al., 2021)

Investigations of fish used in spas have also identified potentially zoonotic organisms including Streptococcus agalactiae and other bacteria. (Verner-Jeffreys et al., 2012)

A noninfectious complication called onychomadesis, in which a nail separates and may eventually shed, has also been reported after a fish pedicure. The authors considered repeated trauma to the nail matrix a possible explanation. (Lipner, 2018)

These reports do not establish that serious complications are common. They demonstrate, however, that the risk is biologically real rather than merely theoretical.

There is no well-established treatment schedule.

In the best-known psoriasis study, patients received daily treatment over three weeks. The average patient-reported remission period was approximately 8.6 months, although there was substantial variation among patients. (Grassberger & Hoch, 2006)

Those results should be interpreted carefully because:

• patients received UVA treatment as well;
• the study was retrospective;
• there was no untreated control group; and
• patient follow-up relied partly on questionnaires.

A commercial fish pedicure is very different. Cosmetic exfoliation may make skin feel smoother immediately, but the effect is generally temporary because the skin continues its normal cycle of growth and shedding.

More research would be required before an evidence-based schedule for medical ichthyotherapy could be recommended.

13. Can ichthyotherapy be combined with other psoriasis treatments?

Yes, and the best-known published study actually used ichthyotherapy together with ultraviolet A exposure.

Removing thick scales may theoretically improve penetration of light or topical treatments by reducing material covering the plaque.

However, combining treatments creates an important scientific problem: if the patient improves, it may be difficult to determine which part of the treatment caused the improvement.

Modern psoriasis treatment includes topical medications, phototherapy, systemic drugs, and biologic medications with much larger evidence bases than ichthyotherapy.

Therefore, a patient with psoriasis should not stop prescribed therapy or substitute fish treatment without discussing the decision with a clinician.

14. What is the difference between medical ichthyotherapy and a fish pedicure?

This distinction is fundamental.

Medical ichthyotherapy uses fish as part of an attempt to treat a diagnosed skin disease. Ideally, patients are screened medically, contraindications are considered, treatment is monitored, and outcomes are assessed.

A fish pedicure is primarily a cosmetic or recreational service. The goal is usually softer-feeling skin or an unusual spa experience.

The biological action may be similar (fish grazing the superficial skin) but the purpose and circumstances differ.

A short fish-spa session should therefore not be described as equivalent to the prolonged treatment regimens investigated for psoriasis.

Likewise, evidence suggesting benefit from a medically supervised psoriasis program cannot automatically be used to advertise a commercial pedicure as a treatment for psoriasis or other diseases.

15. Where can someone receive ichthyotherapy, and what should they ask the provider?

The most historically famous site is the Kangal thermal spring region of Türkiye, where naturally occurring doctor fish became associated with treatment of psoriasis.

Commercial fish spas have also operated in many countries, although legal status varies considerably.

A person considering a facility should ask:

• What species of fish are being used?
• How is the species verified?
• Are new clients screened for wounds and infection risks?
• How is water quality monitored?
• How is the filtration system maintained?
• Are tanks shared among customers?
• Are the fish moved between tanks?
• How is fish health monitored?
• What happens if a fish becomes ill?
• What procedures are used after a customer bleeds or develops a skin injury?
• Is the facility licensed or inspected by a relevant public-health or cosmetology authority?
• If treatment is being offered for a disease, is a qualified health professional involved?

A beautifully maintained facility may reduce risk, but it cannot eliminate the fundamental sanitation problem created by repeatedly using living fish.

16. Is ichthyotherapy an approved or standard medical treatment?

No.

Ichthyotherapy is not a standard first-line medical treatment for psoriasis in the United States, nor should it be regarded as equivalent to established topical, phototherapeutic, systemic, or biologic treatments.

Published evidence remains too limited to establish its effectiveness with the confidence expected for conventional psoriasis therapies.

It is best described as a complementary or investigational form of biotherapy for selected hyperkeratotic skin conditions.

That does not mean it has no biological effect. The exfoliation is obvious, and the available psoriasis studies are intriguing.

It means that the scientific evidence is not yet strong enough to establish:

• how much clinical benefit comes from the fish themselves;
• which patients benefit;
• the ideal treatment schedule;
• how ichthyotherapy compares with modern psoriasis treatments;
• how durable the effects are; or
• whether benefits outweigh infection risk in routine clinical practice.

17. Do doctor fish secrete a medicine or special healing enzyme?

Claims of this type should be treated cautiously.

One widely repeated claim is that Garra rufa produces or secretes dithranol, also called anthralin, a medication historically used to treat psoriasis.

There is no scientific evidence that Garra rufa produces dithranol. Dithranol is a defined chemical compound historically derived from plant material and later manufactured synthetically; it is not a known fish secretion. (Grassberger & Sherman, 2013)

Other possible biochemical mechanisms have occasionally been proposed, but they have not been adequately demonstrated.

The mechanism for which there is clear evidence is much simpler: the fish mechanically remove superficial scales and keratinized material.

If future research identifies biologically active substances associated with the fish, those mechanisms should be evaluated experimentally rather than assumed from clinical improvement.

18. Why can’t the fish and water simply be disinfected between patients?

Because methods strong enough to disinfect equipment may harm or kill the fish.

A metal pedicure tool can be chemically disinfected or sterilized. A living Garra rufa cannot be placed in most of those disinfectants.

Researchers have studied disinfectants that might be tolerated by the fish, but chemicals capable of controlling microorganisms can also damage fish skin and gills. (Sirri et al., 2013)

The water itself can be filtered, exchanged, treated, and monitored, but the fish remain biological surfaces capable of carrying microorganisms.

This creates a basic infection-control conflict:

the fish need a biologically suitable aquatic environment, while infection control seeks conditions that remove or kill microorganisms.

That conflict is one of the main reasons regulatory authorities have treated fish spas differently from ordinary pedicure services.

19. Can ichthyotherapy be used to clean or debride open wounds?

This is an especially important distinction in the context of biotherapy.

Ichthyotherapy should not be confused with maggot debridement therapy.

Medicinal maggots used for wound care are produced under controlled conditions as medical-grade organisms and are intentionally applied to wounds to remove necrotic tissue.

Garra rufa in fish spas are not sterile or disinfected medical devices. Open wounds create a route through which aquatic microorganisms may enter tissue.

For that reason, open wounds, broken skin, and active infection are generally reasons not to use commercial fish-spa treatment.

Although historical descriptions sometimes claim that doctor fish “heal wounds,” current evidence does not justify using ordinary ichthyotherapy as a method of wound debridement.

The removal of superficial psoriasis scales is biologically and clinically different from debriding devitalized tissue from an open wound.

20. What about the health and welfare of the fish?

The welfare of the fish should be considered part of any ethical assessment of ichthyotherapy.

Garra rufa does not naturally live on human skin alone. In the wild, it consumes a varied diet that includes algae, microorganisms, detritus, and other material. (Yilmaz et al., 2025)

Some commercial practices have raised concerns that fish may be deliberately underfed so that they will graze human skin more aggressively. The CDC specifically lists potential starvation of fish among the concerns associated with commercial fish pedicures. (Centers for Disease Control and Prevention, 2024)

Appropriate husbandry should therefore include:

• adequate species-appropriate nutrition;
• suitable water temperature and chemistry;
• sufficient oxygenation;
• appropriate stocking density;
• veterinary or aquatic-animal health oversight;
• monitoring for infectious disease;
• adequate rest from repeated human exposure; and
• humane management of sick or injured fish.

There are also environmental concerns.

Garra rufa is not native to North America and other regions where fish spas have operated. Release of unwanted fish into waterways could introduce a non-native species or associated pathogens. The U.S. Fish and Wildlife Service and CDC have therefore identified environmental release as another concern.

The ethical question is consequently broader than whether ichthyotherapy benefits the patient. A responsible biotherapy program should consider the welfare of both species involved.

References

Centers for Disease Control and Prevention. (2012). Zoonotic disease pathogens in fish used for pedicure. Emerging Infectious Diseases, 18(6).
CDC full-text article

Centers for Disease Control and Prevention. (2024). Healthy habits: Foot hygiene – Fish pedicures and spas.
CDC fish-pedicure guidance

Grassberger, M., & Hoch, W. (2006). Ichthyotherapy as alternative treatment for patients with psoriasis: A pilot study. Evidence-Based Complementary and Alternative Medicine, 3(4), 483-488. https://doi.org/10.1093/ecam/nel033.
PubMed record
Free full text

Grassberger, M., & Sherman, R. A. (2013). Ichthyotherapy. In M. Grassberger, R. A. Sherman, O. S. Gileva, C. M. H. Kim, & K. Y. Mumcuoglu (Eds.), Biotherapy – History, Principles and Practice: A Practical Guide to the Diagnosis and Treatment of Disease Using Living Organisms (pp. 147-176). Springer. https://doi.org/10.1007/978-94-007-6585-6_6.
Chapter record
Book record

Lipner, S. R. (2018). Onychomadesis following a fish pedicure. JAMA Dermatology, 154(9), 1091-1092. https://doi.org/10.1001/jamadermatol.2018.1827.
PubMed record

Shih, Y.-H., et al. (2020). Fish pedicure: Review of its current dermatology applications. Journal of Cutaneous Medicine and Surgery.
PubMed record
Free full text

Sirri, R., Zaccaroni, A., Di Biase, A., Mordenti, O., Stancampiano, L., Sarli, G., & Mandrioli, L. (2013). Effects of two water disinfectants (chloramine T and peracetic acid) on the epidermis and gills of Garra rufa used in human ichthyotherapy. Polish Journal of Veterinary Sciences, 16(3), 453-461. https://doi.org/10.2478/pjvs-2013-0063.
PubMed record

Vanhooteghem, O., Theate, I., & De Schaetzen, V. (2021). Periungual Mycobacterium marinum infection following a fish manicure. Skin Appendage Disorders, 7(5), 393-396. https://doi.org/10.1159/000514853.
PubMed record and free full text

Veraldi, S., Nazzaro, G., & Çuka, E. (2014). Staphylococcus aureus infection of the feet following fish pedicure. Infection, 42(5), 925–926. https://doi.org/10.1007/s15010-014-0622-4.
PubMed record

Yilmaz, S., et al. (2025). Potential of Garra rufa as a novel high-temperature resistant model fish: A review on current and future approaches. Zoological Letters.
Free full-text review