Doctor fish
A stream-dwelling grazer that became internationally known through skin-treatment spas, where it is kept in conditions unlike anything in its range. As an aquarium fish it wants cold fast water, hard rock surfaces and a group, and it becomes territorial with age.
Quick profile
- Scientific name
- Garra rufa
- Adult size
- 10–14 cm (3.9–5.5 in)
- Lifespan
- 5–8 years
- Temperature
- 18–26 °C (64–79 °F)
- pH
- 7–8
- Hardness
- 8–20 °dGH
- Minimum tank
- 150 L (40 US gal)
- Minimum length
- 100 cm
- Swimming zone
- Bottom
- Social
- Loose group — at least 5
- Diet
- Algae grazer
- Overall confidence
- moderate confidence
What keeping this species involves
Hardy and easy to feed, and wanting a cool, fast, hard-water rock tank rather than a warm still community one. The mismatch is the difficulty.
Fast rocky streams and spring-fed pools, including geothermally warmed water, over stone with heavy biofilm growth.
Identity and names
- Common name
- Doctor fish
- Scientific name
- Garra rufa
- Family
- Cyprinidae
- Order
- Cypriniformes
- Class
- Actinopterygii
- Also sold as
- Garra rufa, red garra, nibble fish, kangal fish
Adult size and growth
10–14 cm (3.9–5.5 in)
Typical lifespan in an aquarium: 5–8 years. Almost every animal sold in a shop is a juvenile, so the tank has to suit the size in the first line rather than the size in the bag.
Shape, which is what the compatibility engine reads instead of length alone: fusiform — the ordinary torpedo with a grazing or sucking mouth. A ventral sucker mouth. No fish is at risk of being eaten by it.
Water and tank requirements
A group of stream fish that graze rock surfaces and hold small territories on them. The area is set by the number of grazing stations rather than by fish length.
Temperature (°C)
Scale: 0 to 36 °C.
pH (pH)
Scale: 4 to 9.5 pH.
Hardness (°dGH)
Scale: 0 to 30 °dGH.
Why these ranges: Anatolian and Mesopotamian limestone streams: hard, alkaline and cooler than tropical. The species survives the warm spa water it is famous for and that is a tolerance of an artificial situation rather than a preference.
Where these figures come from
Habitat class
Hard alkaline water — Tigris-Euphrates spring-fed and geothermal pools
Water draining limestone, gypsum or volcanic mineral — Central American rivers, karst springs, hard-water lakes.
These species are usually easy in hard tap water and difficult in the soft, acidic water the hobby treats as the default. The commonest failure is the keeper softening water that did not need softening.
- Conductivity
- 300–900 µS/cm
- Flow
- moderate
- Dissolved oxygen
- moderate
- Seasonality
- moderate
These are figures for the KIND of water body, not measurements of this species. They are AquariumHQ’s summary of the general limnology and are given wide because the water is.
- TemperatureReasoned on this record
- This record states its own reason for this band. See the water section.
- pHReasoned on this record
- This record states its own reason for this band. See the water section.
- General hardnessReasoned on this record
- This record states its own reason for this band. See the water section.
| Requirement | Value | Notes |
|---|---|---|
| Temperature | 18–26 °C (64–79 °F) | Stability matters more than hitting an exact figure. |
| pH | 7–8 | A stable pH outside the ideal band is usually better than an unstable one inside it. |
| General hardness | 8–20 °dGH | Check your supplier's published figure before choosing species. |
| Minimum volume | 150 L (40 US gal) | A floor, not a recommendation. |
| Minimum footprint | 100 cm long × 40 cm deep | A group of stream fish that graze rock surfaces and hold small territories on them. The area is set by the number of grazing stations rather than by fish length. |
| Water flow | high | Match the outflow to this rather than to the filter's rating. |
| Lid required | Recommended | Reduces evaporation and prevents accidents. |
| Structure | Smooth rounded stone and gravel with strong flow across it. Biofilm on hard surfaces is both the food and the territory. |
Behaviour
- Attaches to smooth surfaces with the modified lower lip and grazes in short scraping arcs.
- Rasps at the skin of larger slow-moving fish where biofilm is available, which is the behaviour the spa trade uses and is unwelcome to the fish being rasped.
Telling males from females
Males develop breeding tubercles on the head and snout in condition. Outside that there is no reliable difference.
Feeding
Grazes biofilm and algae from rock. It will take prepared food and it is a rasping grazer rather than a picker, so flat surfaces to work matter as much as the food itself.
- Diet type
- Algae grazer
- Staples
- Algae wafers, Blanched courgette, Spirulina flake, Frozen bloodworm
Breeding
- Strategy
- Eggs scattered over gravel in flowing water
- Difficulty
- challenging
- Parental care
- none
Tankmates and compatibility
Assessments are derived from stored traits by the compatibility engine, with the reasoning shown. A verdict is a statement about probability, not a guarantee — individual temperament can override it.
| Towards | Risk | What it means |
|---|---|---|
| Small fish | none | Anything that fits in the mouth is at risk once this species reaches adult size. |
| Adult dwarf shrimp | none | Cover reduces losses but rarely prevents them where the risk is high. |
| Shrimplets | low | Determines whether a shrimp colony can grow rather than merely persist. |
| Snails | none | Applies to snails you wanted as well as snails you did not. |
| Long or trailing fins | none | Fin damage is an entry point for secondary infection. |
| Plants | grazes-algae | Tough species such as Anubias and Java fern survive most grazers. |
Assessed pairings
Any pair in the catalogue can be assessed with the compatibility checker.
Welfare considerations
Points where the way this species is commonly sold or kept differs from what it actually needs.
- Spa use raises documented welfare and public-health questions, including starvation as a way of encouraging the fish to feed on skin, and several jurisdictions restrict or prohibit the practice.
- Sold into warm community tanks where it lives shorter and grows faster than in its own conditions. The cooler band published here is the fish's rather than the industry's.
Problems to watch for
Most problems in a tank containing this species are general rather than species-specific. Start with the troubleshooting index and work from the observation rather than from a guess at the cause.
What AquariumHQ does not yet hold
Species-level disease susceptibility is modelled in the graph and is not yet populated. Health pages will not be published until each condition has veterinary sourcing, because health content written without evidence is the most harmful thing this product could publish. The gap is recorded in the coverage report.
Where it comes from
- Native range
- The Tigris and Euphrates basins and adjacent drainages — Turkey, Syria, Iraq and Iran
- Habitat
- Fast rocky streams and spring-fed pools, including geothermally warmed water, over stone with heavy biofilm growth.
What the checklists say
3 distribution statements retrieved from GBIF checklists. Establishment means is reproduced from the source where it states one, and left unstated where it does not — a record of presence is not a record of origin.
| Status | Places | What this means |
|---|---|---|
| Recorded as present, establishment means not stated | 3 | The source records the species as present and does not say whether it is native or introduced. AquariumHQ does not fill that in. |
No checklist AquariumHQ holds positively calls this species native anywhere, so the native range above rests on AquariumHQ’s own reading of the literature rather than on a cited checklist.
Legal status and responsible practice
Restriction note
The use of this species in skin-treatment establishments is restricted or prohibited in a number of jurisdictions on welfare and hygiene grounds. Those rules concern commercial use rather than private aquarium keeping, and vary considerably; check the position that applies locally.
Never release aquarium life into the wild
Aquarium animals, plants, and aquarium water must never be released into ponds, rivers, canals, drains or the sea — not even in a country where the species is sold freely. Released fish and invertebrates establish populations that displace native species, and released plants and water carry pathogens, parasites and fragments capable of spreading without any animal at all. If you can no longer keep an animal, rehome it through an aquarium society, a retailer that accepts returns, or another keeper.
- Rehome through a local aquarium society, a specialist retailer or another keeper.
- Unwanted plants go in household waste or a hot compost heap, never in a watercourse or a garden pond.
- Never empty a bucket of tank water into a drain that discharges to open water.
- If an animal is beyond rehoming, ask an aquatic veterinarian about humane euthanasia rather than releasing it.
Legal status is recorded from the sources named and was correct on the verification date shown. Rules change, and sub-national rules often differ from national ones. Check the current position with the relevant authority before acquiring, selling or moving any animal or plant.
Evidence
Every stored value with the kind of support behind it and where to check it. Evidence type and confidence are separate axes: an editorial position held confidently and a measurement held tentatively are different things.
| Claim | Value | Evidence type | Confidence | Source |
|---|---|---|---|---|
| scientific name | Garra rufa | Observed / measured | high confidence | Catalogue of Life; GBIF — Global Biodiversity Information Facility |
| native range | The Tigris and Euphrates basins and adjacent drainages — Turkey, Syria, Iraq and Iran | Observed / measured | moderate confidence | GBIF — Global Biodiversity Information Facility |
| adult size | 10–14 cm | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| lifespan | 5–8 years | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| temperature | 18–26 °C | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| ph | 7–8 pH | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| general hardness | 8–20 °dGH | Aquarium-literature consensus | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank volume | ≥ 150 L | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
| minimum tank length | ≥ 100 cm | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
| minimum group size | ≥ 5 | AquariumHQ editorial position | moderate confidence | AquariumHQ husbandry synthesis |
Last reviewed 2026-08-10. Values labelled as an aquarium-literature consensus are AquariumHQ editorial positions rather than measurements — see how evidence is handled.
Why we say this
What each figure on this page rests on, and how far that is from being independently established.
Every figure on this page has a provenance. Open any claim to see what AquariumHQ holds for it, which sources say what, and what a claim of that kind actually needs. Different claims need different evidence: an accepted scientific name is settled by one authority, while a legal restriction needs a current primary instrument. A single source is often the right answer rather than a thin one.
scientific nameAquariumHQ's own position, externally checkableBased on a verified authoritative source.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: accepted scientific name and classification — 1 authoritative source in an appropriate context. Checked against gbif on 2026-08-29. One authoritative backbone is what this class requires.
What would improve this: Go and read a source. This is reachable and has not been reached.
native rangeAquariumHQ's own position, externally checkableLimited evidence — treat with caution.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: where the species occurs — 1 authoritative source in an appropriate context. 3 distribution statements held, and not one of them states an establishment means. Presence without native-or-introduced is not a native-range claim, so this stays below requirement rather than being read as one.
What would improve this: Go and read a source. This is reachable and has not been reached.
adult sizeAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: size a well-kept specimen reaches — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
lifespanAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
temperatureAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
phAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
general hardnessAquariumHQ's own position, externally checkableAquariumHQ's own position, derived from evidenced inputs.
AquariumHQ's own position on a claim an external source could support.
What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Go and read a source. This is reachable and has not been reached.
minimum tank volumeAquariumHQ's judgement — no authority publishes thisAquariumHQ's own position, derived from evidenced inputs.
No external authority publishes this. The rationale carries the reasoning.
What this kind of claim needs: minimum tank size — no external source is required, provided AquariumHQ shows its reasoning. No authority publishes this. AquariumHQ derives it, and the derivation is recorded with its inputs and assumptions.
What would improve this: Keep the rationale current. There is no source to find.
minimum tank lengthAquariumHQ's judgement — no authority publishes thisAquariumHQ's own position, derived from evidenced inputs.
No external authority publishes this. The rationale carries the reasoning.
What this kind of claim needs: minimum tank size — no external source is required, provided AquariumHQ shows its reasoning. No authority publishes this. AquariumHQ derives it, and the derivation is recorded with its inputs and assumptions.
What would improve this: Keep the rationale current. There is no source to find.
minimum group sizeAquariumHQ's judgement — no authority publishes thisAquariumHQ's own position, derived from evidenced inputs.
No external authority publishes this. The rationale carries the reasoning.
What this kind of claim needs: group size — no external source is required, provided AquariumHQ shows its reasoning. No external source is required for this class. AquariumHQ's position stands on its stated reasoning.
What would improve this: Keep the rationale current. There is no source to find.
Guides relevant to this species
Chosen from this record's own traits rather than listed on every page.
- Schooling and shoalingThis species is recorded as loose group, and the number it is kept in decides how it behaves.
- Native, introduced and invasiveThis record carries an invasive or legal note, and those are five separate claims that are easy to read as one.
- Wild conditions and aquarium recommendationsThe water band on this page is an AquariumHQ position with a stated reason, not a measurement of a river.
Group size and social behaviour
Lives in loose aggregations that develop a pecking order as the fish mature. Kept in small numbers the dominant fish concentrates on one target.