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CrayfishfreshwaterDemanding

Noble crayfish

Europe's largest native crayfish and, until the twentieth century, its most abundant. Crayfish plague carried by introduced North American species has removed it from most of its range, and it is protected in many countries.

Quick profile

Scientific name
Astacus astacus
Adult size
12–18 cm (4.7–7.1 in)
Lifespan
10–20 years
Temperature
4–22 °C (39–72 °F)
pH
7–8.5
Hardness
10–25 °dGH
Minimum tank
150 L (40 US gal)
Minimum length
100 cm
Swimming zone
Bottom
Social
Loose group — at least 1
Diet
Omnivore
Overall confidence
moderate confidence

What keeping this species involves

Cool hard well-oxygenated water and a large floor. It is also a protected species in much of Europe, which is the more consequential constraint.

Cool clean rivers, streams and lakes with hard water, rock and undercut banks.

Identity and names

Common name
Noble crayfish
Scientific name
Astacus astacus
Family
Astacidae
Order
Decapoda
Class
Malacostraca
Also sold as
Astacus astacus, European crayfish, broad-fingered crayfish

Adult size and growth

12–18 cm (4.7–7.1 in)

Typical lifespan in an aquarium: 10–20 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: depressed — flattened top to bottom with a moderate. Assigned from what is typical of Astacidae, not examined for this species.

Water and tank requirements

A large cool-water crayfish. Where keeping it is permitted at all, it needs floor area, cool water and shelters; in most of its range it is protected and cannot be taken from the wild.

Temperature (°C)

Noble crayfish
4–22

Scale: 0 to 36 °C.

pH (pH)

Noble crayfish
7–8.5

Scale: 4 to 9.5 pH.

Hardness (°dGH)

Noble crayfish
10–25

Scale: 0 to 30 °dGH.

The bands AquariumHQ publishes for the noble crayfish, each drawn against the full range this catalogue uses for that parameter. A narrow band on a wide scale is a specialist; a wide one is a genuinely tolerant animal. Source: AquariumHQ husbandry position for this record — an editorial range, not a measurement

Why these ranges: Cool clean European rivers with hard water. The hardness is genuinely required for shell formation in a large crayfish, and the temperature ceiling is a real limit rather than a preference — this species is a cold-water animal.

Where these figures come from

Habitat class

Temperate still water

Ponds, lakes, canals and slow rivers outside the tropics, with a genuine winter.

The temperature range is the point. These animals experience a seasonal cycle, and keeping them at a constant tropical temperature shortens their lives without ever looking like the cause.

Conductivity
150–800 µS/cm
Flow
still
Dissolved oxygen
variable
Seasonality
strong

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 hardnessSet by a requirement of the animal
Hardness here is set by moulting rather than by habitat. A crayfish rebuilds its entire exoskeleton several times a year and draws the calcium for it from the water and from its own gastroliths; in soft water the moult is where the animal dies. The band is a provision for that, and it is deliberately firmer than some of these species' recorded habitat.
RequirementValueNotes
Temperature4–22 °C (39–72 °F)Stability matters more than hitting an exact figure.
pH7–8.5A stable pH outside the ideal band is usually better than an unstable one inside it.
General hardness10–25 °dGHCheck your supplier's published figure before choosing species.
Minimum volume150 L (40 US gal)A floor, not a recommendation.
Minimum footprint100 cm long × 45 cm deepA large cool-water crayfish. Where keeping it is permitted at all, it needs floor area, cool water and shelters; in most of its range it is protected and cannot be taken from the wild.
Water flowmoderateMatch the outflow to this rather than to the filter's rating.
Lid requiredRecommendedReduces evaporation and prevents accidents.
StructureRock, undercut shelters and cool well-oxygenated water. A covered tank.

Group size and social behaviour

Territorial and cannibalistic around moults, as crayfish generally are. It is displaced by the introduced North American species wherever they meet.

Structure
Loose group
Minimum group
1

Behaviour

  • Shelters under rock and in bank undercuts during the day and forages at night.
  • Extremely susceptible to crayfish plague, which kills entire populations within weeks of arriving in a river.

Telling males from females

Males have larger claws and a narrower abdomen; females have a broader abdomen for carrying eggs.

Feeding

Eats plant material, invertebrates and carrion. Slower-growing and later-maturing than the introduced species that have replaced it, which is part of why it loses the competition.

Diet type
Omnivore
Staples
Sinking pellets, Blanched vegetables, Frozen fish, Alder leaves

Breeding

Strategy
Eggs carried beneath the female's abdomen through the winter and into spring
Difficulty
challenging
Parental care
carries eggs

Maturity takes three to four years and broods are small, which makes recovery from a plague outbreak very slow.

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.

Risk this species poses to common tankmates
TowardsRiskWhat it means
Small fishhighAnything that fits in the mouth is at risk once this species reaches adult size.
Adult dwarf shrimpnear-certainCover reduces losses but rarely prevents them where the risk is high.
Shrimpletsnear-certainDetermines whether a shrimp colony can grow rather than merely persist.
Snailsnear-certainApplies to snails you wanted as well as snails you did not.
Long or trailing finsnoneFin damage is an entry point for secondary infection.
PlantsconsumesTough species such as Anubias and Java fern survive most grazers.

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.

  • Assessed as threatened and legally protected in a number of European countries, where taking it from the wild is an offence.
  • Cannot be kept in the same system as any North American crayfish, and equipment moved between tanks can carry the plague organism.

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
Europe — from France and Britain east to Russia, in cool clean rivers and lakes
Habitat
Cool clean rivers, streams and lakes with hard water, rock and undercut banks.

What the checklists say

47 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.

StatusPlacesWhat this means
Native4A checklist states the species occurs here naturally.
Introduced37A checklist states the species arrived here with human help. That is not a statement that it is established, harmful or illegal.
Recorded as present, establishment means not stated6The source records the species as present and does not say whether it is native or introduced. AquariumHQ does not fill that in.

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.

ClaimValueEvidence typeConfidenceSource
scientific nameAstacus astacusObserved / measuredhigh confidenceCatalogue of Life; GBIF — Global Biodiversity Information Facility
native rangeEurope — from France and Britain east to Russia, in cool clean rivers and lakesObserved / measuredmoderate confidenceGBIF — Global Biodiversity Information Facility
adult size12–18 cmAquarium-literature consensusmoderate confidenceAquariumHQ husbandry synthesis
lifespan10–20 yearsAquarium-literature consensusmoderate confidenceAquariumHQ husbandry synthesis
temperature4–22 °CAquarium-literature consensusmoderate confidenceAquariumHQ husbandry synthesis
ph7–8.5 pHAquarium-literature consensusmoderate confidenceAquariumHQ husbandry synthesis
general hardness10–25 °dGHAquarium-literature consensusmoderate confidenceAquariumHQ husbandry synthesis
minimum tank volume≥ 150 LAquariumHQ editorial positionmoderate confidenceAquariumHQ husbandry synthesis
minimum tank length≥ 100 cmAquariumHQ editorial positionmoderate confidenceAquariumHQ husbandry synthesis
minimum group size≥ 1AquariumHQ editorial positionmoderate confidenceAquariumHQ 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 checkableBased on a verified authoritative source.

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. 47 distribution statements held from GBIF checklists — native in 4, introduced in 37 countries. Establishment means is reproduced from the source, never inferred from occurrence.

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.