Mystery snail (Pomacea bridgesii) — care and compatibility

What keeping this species involves

Hardy given hard alkaline water, calcium and an air gap at the surface.

Slow, vegetated fresh water.

Identity and names

Common name: Mystery snail
Scientific name: Pomacea bridgesii
Family: Ampullariidae
Order: Architaenioglossa
Class: Gastropoda
Also sold as: apple snail, golden mystery snail, pomacea
Former or synonymous names: Pomacea diffusa

Name ambiguity

The aquarium 'mystery snail' is Pomacea diffusa (long traded as P. bridgesii). It is a detritus feeder and does NOT eat healthy plants — unlike Pomacea canaliculata, a serious agricultural pest that is banned in the EU and elsewhere.

Adult size and growth

4–6 cm (1.6–2.4 in)

Typical lifespan in an aquarium: 1–3 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.

Water and tank requirements

A 5 cm snail with a substantial appetite and waste output, needing an air gap above the waterline to breathe and lay.

Requirement	Value	Notes
Temperature	20–28 °C (68–82 °F)	Stability matters more than hitting an exact figure.
pH	7–8.5	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.
Carbonate hardness	4–15 °dKH	Buffering capacity — what stops the pH moving.
Minimum volume	40 L (11 US gal)	A floor, not a recommendation.
Minimum footprint	45 cm long	A 5 cm snail with a substantial appetite and waste output, needing an air gap above the waterline to breathe and lay.
Water flow	low	Match the outflow to this rather than to the filter's rating.
Lid required	Recommended	Reduces evaporation and prevents accidents.

Group size and social behaviour

Indifferent to others; a mixed-sex pair will breed.

Structure: Tolerant of any grouping

Behaviour

Extends a long breathing siphon to the surface — normal, not a sign of poor oxygen.
Falls off the glass and lands upside down; it can usually right itself, but check.

Telling males from females

Not externally distinguishable without inspecting the animal directly.

Feeding

Eats decaying plant material, not living leaves. Damage attributed to it is usually caused by something else.

Diet type: Detritivore
Staples: Detritus, Blanched vegetables, Sinking foods, Algae, Dead and dying plant matter

Breeding

Strategy: Lays a pink calcified egg clutch ABOVE the waterline
Difficulty: incidental
Parental care: none

The clutch is laid in air and will not develop if submerged, which makes population control straightforward.

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
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	none	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	none	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.

Fill the tank short of the rim. Without an air gap the snail cannot breathe or lay.
Requires calcium and adequate KH for shell growth.
Do not confuse with Pomacea canaliculata, which is listed as an invasive alien species of Union concern in the EU and is prohibited there.

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: Amazon basin
Habitat: Slow, vegetated fresh water.

What the checklists say

16 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
Native	2	A checklist states the species occurs here naturally.
Introduced	9	A 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 stated	5	The source records the species as present and does not say whether it is native or introduced. AquariumHQ does not fill that in.

Legal status and responsible practice

Restriction note

Trade in apple snails is restricted in the EU because of Pomacea canaliculata's status as an invasive alien species of Union concern. Check what is permitted in your jurisdiction and never release any apple snail or its eggs.

What AquariumHQ has recorded, by jurisdiction, with the instrument each entry comes from and how far the check went. Ecological risk and legal status are separate: a species can be ecologically risky and legally unrestricted, or restricted where it could never establish.

EU

Prohibitedimport

The EU restriction on apple snails is a plant-health measure, not an invasive-species listing. It is directed at preventing the establishment and spread of the genus Pomacea within the Union and at eradicating it where found, on the basis that these snails damage aquatic plants. The genus-level scope is what catches aquarists: a snail sold as a 'mystery snail' is a Pomacea.

Instrument: Commission Implementing Regulation (EU) 2024/2013 of 23 July 2024 on measures to prevent the establishment and spread within the Union territory and to eradicate Pomacea (Perry), applicable from 26 January 2025

TWO CORRECTIONS, ONE STILL OPEN. Mega Sprint 2 attributed this restriction to the list of invasive alien species of Union concern under Regulation (EU) No 1143/2014; the Union list annex contains no Pomacea entry and its crayfish entries are named species rather than genera, so that was wrong. Mega Sprint 3 corrected it to Decision 2012/697/EU, read the Decision, and recorded that it could not tell whether the Decision survived Regulation (EU) 2016/2031. It did not: it was repealed and replaced by Implementing Regulation (EU) 2024/2013. AquariumHQ has established the repeal and the identity of the replacement from the EU's own legislative record, but has NOT been able to open the operative text of 2024/2013 — EUR-Lex returned no document body on the attempts made on 2026-08-11. This entry is therefore downgraded from primary-source-checked, and the conclusion it supports is deliberately limited to what the title and legislative history state: the genus is subject to EU plant-health measures aimed at preventing its spread. Anything more specific — exactly which acts are prohibited, and what follows for a snail already in a private aquarium — must be confirmed with the national plant health authority.

Instrument recorded, species entry not re-checked · last checked 2026-08-11 · AquariumHQ has recorded the instrument and what it does, but has not re-confirmed this species' entry against the current consolidated text. Listings are amended, so treat this as a pointer to the right law rather than as a confirmation of the current position, and check with the authority before acting.

EU

Restrictedpossession

The EU measures address introduction, establishment and spread rather than private keeping as such, and the practical effect of the regime since 2012 has been to end apple-snail imports into the EU. What that means for a snail already in a private aquarium is not something AquariumHQ can state from the instrument alone.

Instrument: Commission Implementing Regulation (EU) 2024/2013

Carried forward from the repealed Decision 2012/697/EU to its replacement. The genus-level scope is genuine and is the detail that catches aquarists: a snail sold as a 'mystery snail' is a Pomacea. Because the operative text of the replacing regulation has not been read, the position on private possession is stated here as unresolved rather than narrowed. Confirm with the national plant health authority before acquiring, selling or moving these animals.

Instrument recorded, species entry not re-checked · last checked 2026-08-11 · AquariumHQ has recorded the instrument and what it does, but has not re-confirmed this species' entry against the current consolidated text. Listings are amended, so treat this as a pointer to the right law rather than as a confirmation of the current position, and check with the authority before acting.

CA

Not verified by AquariumHQpossession

The federal schedule was read in full on 2026-08-11 and contains no entry for Pomacea or for any apple snail. No restriction was identified in that instrument. That is not a finding that keeping, selling or moving apple snails is lawful in Canada: the schedule is federal, the provinces legislate separately and have not been checked here, and schedules are amended. Check with the relevant authority before acquiring, selling or moving any animal.

Instrument: Aquatic Invasive Species Regulations (SOR/2015-121), Schedule

The contrast with the EU is the useful part. The same animal is caught by an EU plant-health measure drawn at genus level and is absent from Canada's federal aquatic-invasive schedule entirely — and Canadian provinces legislate separately, none of which has been checked here. A keeper cannot reason from one jurisdiction to another, and AquariumHQ should not either.

Checked against the instrument · last checked 2026-08-11 · An editor has read the current text of the named instrument and confirmed this species' entry on the date shown.

NZ

Restrictedimport

New Zealand operates a permitted list. An aquatic animal may be imported only if it appears in an import health standard, and the ornamental standard carries its list of approved species in an appendix. A species absent from that appendix cannot be imported. Imported stock must additionally pass through an approved transitional facility, with a quarantine period of several weeks.

Instrument: Biosecurity Act 1993 — import health standard for ornamental fish and marine invertebrates

WHAT 'NOT ON THE LIST' MEANS DEPENDS ENTIRELY ON THE JURISDICTION, and New Zealand inverts the usual reading. Everywhere AquariumHQ records a negative finding, the rule is that absence from a prohibited list proves nothing. Under a permitted-list regime the opposite holds: absence from the approved list IS the prohibition. AquariumHQ has established that New Zealand works this way but has NOT read the appendix, so whether Pomacea bridgesii appears on it is unknown. That uncertainty runs the other way from the EU entry above — here, not knowing means not being able to say the species may be imported.

Instrument recorded, species entry not re-checked · last checked 2026-08-11 · AquariumHQ has recorded the instrument and what it does, but has not re-confirmed this species' entry against the current consolidated text. Listings are amended, so treat this as a pointer to the right law rather than as a confirmation of the current position, and check with the authority before acting.

GB

Prohibitedrelease

Releasing or allowing to escape any animal not ordinarily resident in Great Britain is an offence. This applies to every non-native aquarium animal without exception, and it does not depend on the species appearing on any list.

Instrument: Wildlife and Countryside Act 1981, section 14 (England and Wales); as amended for Scotland by the Wildlife and Natural Environment (Scotland) Act 2011

Instrument recorded, species entry not re-checked · last checked 2026-08-11 · AquariumHQ has recorded the instrument and what it does, but has not re-confirmed this species' entry against the current consolidated text. Listings are amended, so treat this as a pointer to the right law rather than as a confirmation of the current position, and check with the authority before acting.

US

Restrictedimport

Apple snails are treated as a plant-pest and agricultural risk in the United States, and importation and interstate movement of Pomacea are subject to federal restriction. Several states impose their own prohibitions in addition.

Instrument: Lacey Act injurious wildlife provisions, 18 U.S.C. 42, administered by the US Fish and Wildlife Service; and USDA APHIS plant-pest regulation of apple snails

US federal listing restricts import and interstate transport. It does not by itself make possession unlawful — but state law frequently does, and state law is where most aquarists are actually caught.

Instrument recorded, species entry not re-checked · last checked 2026-08-11 · AquariumHQ has recorded the instrument and what it does, but has not re-confirmed this species' entry against the current consolidated text. Listings are amended, so treat this as a pointer to the right law rather than as a confirmation of the current position, and check with the authority before acting.

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	Pomacea bridgesii	Observed / measured	high confidence	Catalogue of Life; GBIF — Global Biodiversity Information Facility
native range	Amazon basin	Observed / measured	moderate confidence	GBIF — Global Biodiversity Information Facility
adult size	4–6 cm	Aquarium-literature consensus	moderate confidence	AquariumHQ husbandry synthesis
lifespan	1–3 years	Aquarium-literature consensus	moderate confidence	AquariumHQ husbandry synthesis
temperature	20–28 °C	Aquarium-literature consensus	moderate confidence	AquariumHQ husbandry synthesis
ph	7–8.5 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	≥ 40 L	AquariumHQ editorial position	moderate confidence	AquariumHQ husbandry synthesis
minimum tank length	≥ 45 cm	AquariumHQ editorial position	moderate confidence	AquariumHQ husbandry synthesis
carbonate hardness	4–15 °dKH	Aquarium-literature consensus	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 2026-08-11. 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. 16 distribution statements held from GBIF checklists — native in 2, introduced in 8 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.

1–2 years — Ornamental Aquatic Trade Association · Typically observed · The range the species is recorded from

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.

carbonate 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.

Mystery snail

Quick profile

What keeping this species involves

Identity and names

Adult size and growth

Water and tank requirements

Group size and social behaviour

Behaviour

Telling males from females

Feeding

Breeding

Tankmates and compatibility

Assessed pairings

Welfare considerations

Problems to watch for

Where it comes from

What the checklists say

Legal status and responsible practice

EU

EU

CA

NZ

GB

US

Evidence

Why we say this