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Ageneiosus marmoratus
Fishes › Catfish (Siluriformes) › Auchenipteridae (Driftwood catfish)
Ageneiosus inermis, also known as Fidalgo, Dawala or Mandubé, is a species of driftwood catfish of the family Auchenipteridae.
Care at a glance
Species-specific aquarium care
- Tank: At least 42 in long and 15 in front to back for one adult (adults commonly reach about 7.3 in / 18.5 cm).
- Water: Freshwater.
- Temperature: 73–79°F (range recorded for this species).
- Layout: An open-water swimmer: needs long, open swimming space with few obstacles.
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 59 × 24 in (roughly 143 US gallons); space needed is rated “very large tank”.
- Water: soft, acidic water, 72–79 °F, pH 6–7, 3–10 dGH.
- Behaviour: temperament predatory.
- Difficulty: Difficult (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Ideally a soft, sandy substrate should be used though it is not essential.”
- Tankmates: “Surprisingly peaceful with anything too large to swallow and can be maintained in a community provided tankmates are chosen with care.”
- Breeding: “Unrecorded in aquaria although some brief reports of apparent courtship behaviour do exist.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
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.
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.
Climate & lighting
| Water | 71.6–82.4°F |
Diet
- For Trachelyopterus: floating insect-based foods offered when light is low.
- For gulpers: strips of white fish.
- For gulpers: whole shrimp and earthworms.
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.
Health watch
- Ammonia toxicity.
- Nutritional deficiencies.
Understanding the animal
About this animal
About this animal
It can be found throughout South America, from Colombia and Venezuela to Uruguay and northern Argentina. The name Ageneiosus marmoratus has been recently synonymized with A. inermis.
Quoted from the Wikipedia article “Ageneiosus inermis” (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 lives | Lives in freshwater. |
| Water it lives in | Freshwater, 73–79 °F (23–26 °C). |
| Climate | Tropical climate. |
What this means for care
- Keep water within its wild range, 73–79 °F.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 89°F (up to 91°F in the hottest sampled areas) |
| Cool-season lows | about 70°F (down to 69°F in the coldest sampled areas) |
| Average temperature | 79–80°F across sampled records |
| Relative humidity | 80–82% on average (driest month about 75%) |
| Rainfall | about 2274 mm a year |
Measured at 12 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.
| Overview | Ageneiosus inermis, also known as Fidalgo, Dawala or Mandubé, is a species of driftwood catfish of the family Auchenipteridae. It can be found throughout South America, from Colombia and Venezuela to Uruguay and northern Argentina. The name Ageneiosus marmoratus has been recently synonymized with A. inermis. The description was based on a strongly pigmented juvenile of A. inermis. — Wikipedia (community-edited) |
| Where it lives | Home 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 |
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.
Adult length
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
Range the species tolerates in nature; aim for the middle.
pH
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 59 × 24 in (about 143 US gallons).
Sources for this sheet
- 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.
- 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.
- Seriously Fish — Asterophysus batrachus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Tropical Fish Hobbyist — Bottom of the Tank: Driftwood Catfish Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual — Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
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