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No federal permit to keep

Iriri golden nugget pleco

Baryancistrus xanthellus

Fishes › Catfish (Siluriformes) › Loricariidae (Plecos)

Baryancistrus xanthellus is a species of freshwater ray-finned fish belonging to the family Loricariidae, the suckermouth armoured catfishes, and the subfamily Hypostominae, the suckermouth catfishes.

Aquarium hobby
Experience: Easy
Iriri golden nugget pleco
Photo: Anne Blindheim, CC BY-SA 3.0, via Wikimedia Commons
FamilyPlecos
Adult lengthup to 11.7 in
WaterFreshwater

Care at a glance

Species-specific aquarium care

  • Tank: At least 48 in long and 24 in front to back for one adult (adults commonly reach about 11.7 in / 29.7 cm).
  • Water: Freshwater.
  • Layout: Lives on or near the bottom: floor space and hiding places matter more than height.
  • Availability: Rarely or never seen in the aquarium trade; expect to source it from specialists or not at all.

Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.

Care guide

Species care notes

  • Tank: a base of at least 47 × 18 in (roughly 64 US gallons); space needed is rated “large tank”.
  • Water: a fairly wide range, from slightly acidic to slightly alkaline, 81–90 °F, pH 6–8, 3–15 dGH.
  • Behaviour: kept alone; suited to a community tank.
  • Difficulty: Moderate (Seriously Fish rating).

Short excerpts from the species profile:

  • Setup: “Not difficult to maintain under the correct conditions but largely unsuitable for the 'general' community aquarium.”
  • Diet: “Gut analyses of wild specimens revealed the diet to be composed chiefly of algae, particularly diatoms and filamentous genera such as Spirogyra alongside smaller amounts of invertebrates such as chironomids and bryozoans.”
  • Tankmates: “Juveniles are relatively peaceful but males in particular become highly intolerant of conspecifics as they age and typically aggressive towards any other fish viewed as a territorial threat.”
  • Breeding: “The possibly conspecific L081 has been bred on a single occasion.”

From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167

Group care guide

Plecos (suckermouth catfish)

Applies to most species in this group. Habitat: South American rivers. Individual species can differ, so compare with the species numbers above and the linked sources.

Common aquarium bristlenoses are frequently unidentified Ancistrus stocks sold under “cirrhosus”. Verify identification before importing a common-bristlenose care sheet into the true A. cirrhosus record.

Housing & setup

  • Driftwood (some species rasp it for fiber), caves and good flow.
  • Common plecos reach 18–24 in; many smaller species stay under 6 in.

Sources 117119164118266

Diet

  • Algae wafers and vegetables for herbivores; meaty foods for carnivorous species.

Sources 117119164118266

Health watch

  • Starvation if they're expected to live on algae alone.

Sources 117119164118266

Understanding the animal

This species is part of a group that hobbyists, aviculturists or zoos keep widely (Plecos), so it's included for completeness. It may be rare in captivity itself, or not kept at all. Use the group guide as a starting point and look for species-specific advice from experienced keepers.
About this animal

About this animal

This benthic catfish is endemic to Brazil where it is found in the Volta Grande and Xingu River, as well as the area immediately above Belo Monte falls and the Iriri River. It reaches a standard length of 22.4 cm (8.8 in).

Quoted from the Wikipedia article “Baryancistrus xanthellus” (CC BY-SA 4.0) 174

In the wild

In the wild

From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1

Where it livesLives in freshwater. Stays near the bottom. Young individuals form groups of several individuals under flat rocks at the bottom of shallow rapid stretches. Adults occur in larger spaces among and under submerged boulders. Based on three specimens, this species feeds mainly on algae and occasionally on bryozoans and chironomid larvae.
Water it lives inFreshwater.
ClimateTropical climate.
  1. FishBase species summary: Baryancistrus xanthellus
Native climate (measured)

Native climate (measured)

Warm-season highsabout 90°F (up to 92°F in the hottest sampled areas)
Cool-season lowsabout 67°F (down to 64°F in the coldest sampled areas)
Average temperature77–78°F across sampled records
Relative humidity84–85% on average (driest month about 77%)
Rainfallabout 1852 mm a year

Measured at 135 wild occurrence records sampled against WorldClim 2.1 climate data (1970–2000 averages). Air conditions in the range are ecological context, not enclosure settings: microhabitats such as burrows, leaf litter or basking rocks can be cooler, warmer or more humid.

From the sources

From the sources

Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.

OverviewBaryancistrus xanthellus is a species of freshwater ray-finned fish belonging to the family Loricariidae, the suckermouth armoured catfishes, and the subfamily Hypostominae, the suckermouth catfishes. This benthic catfish is endemic to Brazil where it is found in the Volta Grande and Xingu River, as well as the area immediately above Belo Monte falls and the Iriri River. It reaches a standard length of 22.4 cm. — Wikipedia (community-edited)
Where it livesHome ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase
BiologyYoung individuals form groups of several individuals under flat rocks at the bottom of shallow rapid stretches. Adults occur in larger spaces among and under submerged boulders. Based on three specimens, this species feeds mainly on algae and occasionally on bryozoans and chironomid larvae. — FishBase

Data and studies

The numbers

The numbers

Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.

Typical adult weight

Reported18oz
FishBase 16418

Average adult body mass in each database (FishBase gives the maximum recorded weight).

Adult length

Average of sources10.2in
FishBase 16411.7
Seriously Fish species profiles 1678.8

Maximum recorded length. Measured as total length. Fish in home aquariums often stay smaller than wild records.

Water temperature

Reported81–90°F
Seriously Fish species profiles 16781–90

Range the species tolerates; aim for the middle.

pH

Reported6–8
Seriously Fish species profiles 1676–8

Water hardness

Reported3–15dGH
Seriously Fish species profiles 1673–15

Minimum tank footprint

Reported47in
Seriously Fish species profiles 16747

Seriously Fish recommends a tank base of at least 47 × 18 in (about 64 US gallons).

Sources for this sheet

  1. FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
  2. Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
  3. Merck Veterinary Manual: Management of aquarium fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
  4. Merck Veterinary Manual: Types and features of aquatic systems Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
  5. Merck Veterinary Manual: Nutritional diseases of fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
  6. Seriously Fish — Ancistrus sp. “3” / common bristlenose identification Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
  7. Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
  8. iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.