FishfreshwaterSpecialistSpecies complexHigh invasive risk

Common pleco

Sold at 6 cm as an algae eater and reaching 45 cm over a life of fifteen years or more. It is one of the most consistently mis-sold animals in the aquarium trade and one of the most damaging when released.

Quick profile

Scientific name: Pterygoplichthys pardalis
Adult size: 35–50 cm (13.8–19.7 in)
Lifespan: 10–20 years
Temperature: 22–28 °C (72–82 °F)
pH: 6.5–8
Hardness: 4–25 °dGH
Minimum tank: 800 L (211 US gal)
Minimum length: 200 cm
Swimming zone: Bottom
Social: Solitary
Diet: Algae grazer
Overall confidence: high confidence

What keeping this species involves

Adult size and waste output place it far outside home-aquarium keeping for most people, and there are very few rehoming options.

Large rivers and floodplains; burrows into banks.

Identity and names

Common name: Common pleco
Scientific name: Pterygoplichthys pardalis
Family: Loricariidae
Order: Siluriformes
Class: Actinopterygii
Also sold as: suckermouth catfish, janitor fish, plec

Name ambiguity

'Common pleco' covers several large Pterygoplichthys and Hypostomus species sold interchangeably as juveniles. All reach 35–50 cm.

Adult size and growth

35–50 cm (13.8–19.7 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.

Water and tank requirements

An adult approaching half a metre needs a tank it can turn round in and filtration sized for an enormous waste output. There is no honest smaller number.

Requirement	Value	Notes
Temperature	22–28 °C (72–82 °F)	Stability matters more than hitting an exact figure.
pH	6.5–8	A stable pH outside the ideal band is usually better than an unstable one inside it.
General hardness	4–25 °dGH	Check your supplier's published figure before choosing species.
Minimum volume	800 L (211 US gal)	A floor, not a recommendation.
Minimum footprint	200 cm long × 60 cm deep	An adult approaching half a metre needs a tank it can turn round in and filtration sized for an enormous waste output. There is no honest smaller number.
Water flow	moderate	Match the outflow to this rather than to the filter's rating.
Lid required	Recommended	Reduces evaporation and prevents accidents.
Structure	Heavy, stable hardscape and driftwood; the fish will move anything it can.

Behaviour

Rasps the mucus coat of slow flat-bodied fish, causing wounds that become secondary infections.
Uproots planting and undermines hardscape.

Feeding

Stops eating meaningful quantities of algae as it grows, while its waste output keeps rising.

Diet type: Algae grazer
Staples: Algae wafers, Blanched vegetables, Driftwood, Sinking pellets

Breeding

Strategy: Burrow spawner in riverbanks
Difficulty: rarely achieved
Parental care: guarding

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	moderate	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	uproots	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.

AquariumHQ recommends the bristlenose pleco instead in almost every case where a common pleco is being considered.
Established invasive populations exist in Florida, Mexico, Taiwan and elsewhere, where burrowing into riverbanks causes documented erosion damage.

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: Large rivers and floodplains; burrows into banks.

What the checklists say

32 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	22	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	8	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

Restricted or prohibited in several jurisdictions because of established invasive populations. Check local rules before acquiring, and never release under any circumstances.

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.

US

Prohibitedrelease

Established populations exist in warm-water systems in the southern United States, where burrowing into banks causes documented erosion. Release is restricted by state law, and this species reaches a size that makes unwanted adults a recurring problem for public aquaria and rescues.

Instrument: State fish and wildlife regulations; established populations are documented in the USGS Nonindigenous Aquatic Species database

The welfare and the legal problem share a cause: a fish sold at 6 cm reaches a size very few keepers have planned for.

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

Release of any non-native animal is an offence. British waters are too cold for this species to establish, but the prohibition does not depend on whether establishment is likely.

Instrument: Wildlife and Countryside Act 1981, section 14

EU

Not verified by AquariumHQpossession

No restriction was identified in the sources AquariumHQ checked for the EU as of 2026-08-11. That is not a finding that keeping, selling or moving this species is lawful there: sub-national rules, permit regimes and trade-specific requirements exist that these sources do not cover, and lists are amended. Check with the relevant authority before acquiring, selling or moving any animal.

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	Pterygoplichthys pardalis	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	35–50 cm	Aquarium-literature consensus	high confidence	AquariumHQ husbandry synthesis
lifespan	10–20 years	Aquarium-literature consensus	high confidence	AquariumHQ husbandry synthesis
temperature	22–28 °C	Aquarium-literature consensus	high confidence	AquariumHQ husbandry synthesis
ph	6.5–8 pH	Aquarium-literature consensus	high confidence	AquariumHQ husbandry synthesis
general hardness	4–25 °dGH	Aquarium-literature consensus	high confidence	AquariumHQ husbandry synthesis
minimum tank volume	≥ 800 L	AquariumHQ editorial position	moderate confidence	AquariumHQ husbandry synthesis
minimum tank length	≥ 200 cm	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 2026-08-11. 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. 32 distribution statements held from GBIF checklists — native in 2, introduced in 22 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 sizeOne sourceBased on a verified authoritative source.1 citation, 1 independent origin

A single source: fishbase.

35–45 cm — AquariumHQ husbandry synthesis · Typically observed · The range the species is recorded from · checked 2026-08-11
57.8–57.8 cm — FishBase · Maximum recorded · The range the species is recorded from · checked 2026-08-11Corrected on checking from 50–50 cm.
12–18 in — Ornamental Aquatic Trade Association · Typically observed · The range the species is recorded from
50–50 cm — Wikidata · Maximum recorded · The range the species is recorded from
50–50 cm — IUCN Red List of Threatened Species · Maximum recorded · The range the species is recorded from

What this kind of claim needs: size a well-kept specimen reaches — no external source is required, provided AquariumHQ shows its reasoning. One authoritative source, which is what this kind of claim requires. Independent replication would be welcome and is not the standard.

What would improve this: Corroborate against a second, independent source.

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.

temperatureOne sourceAquariumHQ's own position, derived from evidenced inputs.1 citation, 1 independent origin

A single source: fishbase.

23–28 °C — FishBase · Tolerated range · The range the species is recorded from · checked 2026-08-11

What this kind of claim needs: what aquariumhq advises for keeping — no external source is required, provided AquariumHQ shows its reasoning. Derived from the observed range rather than copied from it. The advised band reaches past the observed envelope and carries no individual review. Commercially bred stock is generally more tolerant than wild records suggest, which is the usual explanation, and it has not been established for this species.

What would improve this: Corroborate against a second, independent source.

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 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 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 would improve this: Keep the rationale current. There is no source to find.

Common pleco

Quick profile

What keeping this species involves

Identity and names

Adult size and growth

Water and tank requirements

Group size and social behaviour

Behaviour

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

US

GB

EU

Evidence

Why we say this