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Ageneiosus ucayalensis

Ageneiosus ucayalensis

Fishes › Catfish (Siluriformes) › Auchenipteridae (Driftwood catfish)

Ageneiosus ucayalensis is a species of driftwood catfish of the family Auchenipteridae.

Aquarium hobby
Experience: Advanced
FamilyDriftwood catfish
Adult lengthup to 13.9 in
WaterFreshwater
HabitatLives in freshwater

Care at a glance

Species-specific aquarium care

  • Tank: At least 84 in long and 27 in front to back for one adult (adults commonly reach about 13.9 in / 35.2 cm).
  • Water: Freshwater.
  • Layout: An open-water swimmer: needs long, open swimming space with few obstacles.
  • Diet: A predator: feed meaty foods sized to its mouth (frozen fish, shrimp, worms); it will eat tankmates that fit in its mouth. FishBase classes it as a carnivore.
  • 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 71 × 24 in (roughly 171 US gallons); space needed is rated “very large tank”.
  • Water: a fairly wide range, from slightly acidic to slightly alkaline, 72–82 °F, pH 5.5–7.5, 1–20 dGH.
  • Difficulty: Moderate (Seriously Fish rating).

Short excerpts from the species profile:

  • Setup: “Likely to prefer dim lighting and access to refuges in the form of driftwood, large rocks or lengths of plastic piping.”
  • Tankmates: “This species is capable of consuming large prey items and is likely to be safe only alongside similarly-sized catfishes or pelagic characins such as Brycon, Colossoma or Piaractus, a combination only possible in public aquaria in the vast majority of cases.”
  • Breeding: “Unrecorded in aquaria although some brief reports of apparent courtship behaviour in the congener A.”

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

Group care guide

Driftwood catfish

Applies to most species in this group. Habitat: These American freshwater catfish include nocturnal insect feeders and fish predators; gulpers hunt shallow blackwater tributaries in the Negro and Orinoco systems. Individual species can differ, so compare with the species numbers above and the linked sources.

Level 4 is an editorial rating for predation and size planning. Temperature and minimum base here apply to Asterophysus. Adult gulpers typically need one or two meals weekly; avoid mammal or bird meat and routine feeder fish. Trachelyopterus surface feeding differs from gulper piscivory. The sources do not establish adult housing or temperature limits for the listed Ageneiosus or Auchenipterichthys; the gulper minimum must not be applied automatically.

Housing & setup

  • Provide driftwood, roots and crevice refuges; subdued lighting suits nocturnal gulpers.
  • For Asterophysus batrachus, use a base at least 150 × 60 cm (about 60 × 24 inches), preferably with soft sand.
  • Use canister filtration or a sump for gulper waste, with surface agitation.
  • For gulpers, use a mature system and change 30–50% of the water weekly; source parameters are pH 5.0–7.0 and 1–8 dGH.
  • Keep surface feeding access clear for Trachelyopterus fisheri rather than relying on bottom-only feeding.

Sources 926927928

Climate & lighting

Water71.6–82.4°F

Sources 926927928

Diet

  • For Trachelyopterus: floating insect-based foods offered when light is low.
  • For gulpers: strips of white fish.
  • For gulpers: whole shrimp and earthworms.

Sources 926927928

Social life

  • Trachelyopterus fisheri may be less shy in substantial groups, but reaches nearly 30 cm. Asterophysus is a predatory species-tank fish capable of swallowing surprisingly large tankmates.

Sources 926927928

Health watch

  • Ammonia toxicity.
  • Nutritional deficiencies.

Sources 926927928

Understanding the animal

This species is part of a group that hobbyists, aviculturists or zoos keep widely (Driftwood catfish), 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.
No real photograph of this species is freely available yet. The only images we found were scientific illustrations or maps, so none is shown. It stays on the site because there is evidence it is kept (see “Kept in captivity?”), but it is rarely kept or rarely photographed. If you keep one and can share a photo, we would love to add it.
About this animal

About this animal

It can be found in South America.

Quoted from the Wikipedia article “Ageneiosus ucayalensis” (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, in rivers and streams, mangroves. Occurs in the quiet zones of swamps or the lower parts of stream. Carnivorous. Swims close to the bottom, feeding mainly on fish.
Water it lives inFreshwater.
ClimateTropical climate.
Wild dietHunting macrofauna (predator).
  1. FishBase species summary: Ageneiosus ucayalensis
Native climate (measured)

Native climate (measured)

Warm-season highsabout 90°F (up to 94°F in the hottest sampled areas)
Cool-season lowsabout 70°F (down to 56°F in the coldest sampled areas)
Average temperature76–81°F across sampled records
Relative humidity76–83% on average (driest month about 74%)
Rainfallabout 2156 mm a year

Measured at 93 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.

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
BiologyOccurs in the quiet zones of swamps or the lower parts of stream. Swims close to the bottom, feeding mainly on fish. — 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

Reported9.7oz
FishBase 1649.7

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

Adult length

Average of sources12.7in
FishBase 16413.9
Seriously Fish species profiles 16711.4

Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.

Water temperature

Reported72–82°F
Seriously Fish species profiles 16772–82

Range the species tolerates; aim for the middle.

pH

Reported5.5–7.5
Seriously Fish species profiles 1675.5–7.5

Water hardness

Reported1–20dGH
Seriously Fish species profiles 1671–20

Minimum tank footprint

Reported71in
Seriously Fish species profiles 16771

Seriously Fish recommends a tank base of at least 71 × 24 in (about 171 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. Seriously Fish — Asterophysus batrachus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  4. Tropical Fish Hobbyist — Bottom of the Tank: Driftwood Catfish Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  5. Merck Veterinary Manual — Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
  6. Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.