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No federal permit to keepManduba
Ageneiosus inermis
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 156 in long and 51 in front to back for one adult (adults commonly reach about 25.5 in / 64.8 cm).
- Water: Freshwater.
- Temperature: 72–75°F (range recorded for this species).
- pH: 6.5–7.8.
- Hardness: 0–20 dGH.
- 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: Mostly kept by public aquariums; private keeping is uncommon.
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 157 × 47 in (roughly 1522 US gallons); space needed is rated “very large tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 72–79 °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
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, in rivers and streams. Prefers rivers in overgrown backwaters where the current is not too strong. Reported to be nocturnal. Feeds on fish and crustaceans. The flesh is esteemed for its very fine flavor. Frequently captured with nets, with males difficult to release from the nets because of its strong dorsal spine that is bordered with denticles. |
| Water it lives in | Freshwater, 72–75 °F (22–24 °C), pH 6.5–7.8, hardness 20 dH. |
| Climate | Tropical climate. |
| Wild diet | Hunting macrofauna (predator). |
| Behavior to plan for | Breeding: open water/substratum egg scatterers. |
What this means for care
- Keep water within its wild range, 72–75 °F.
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 90°F (up to 92°F in the hottest sampled areas) |
| Cool-season lows | about 68°F (down to 50°F in the coldest sampled areas) |
| Average temperature | 70–81°F across sampled records |
| Relative humidity | 76–83% on average (driest month about 72%) |
| Rainfall | about 2128 mm a year |
Measured at 45 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 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 |
| Reproduction | Female lays eggs on plants a few days after fertilization. The females can preserve keep fertile spermatozoids by coating these with secretions of maternal origin and inserting these in the epithelium of its genital tract. — FishBase |
| Biology | Prefers rivers in overgrown backwaters where the current is not too strong. Reported to be nocturnal. Feeds on fish and crustaceans. — 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
Average adult body mass in each database (FishBase gives the maximum recorded weight).
Adult length
Maximum recorded length. Measured as total length. Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates in nature; aim for the middle.
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 157 × 47 in (about 1522 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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