Home / Fishes / Catfish / Black-top Mouse Catfish
No federal permit to keepBlack-top Mouse Catfish
Hassar orestis
Fishes › Catfish (Siluriformes) › Doradidae (Thorny catfish)
Hassar orestis is a species of thorny catfish that is native to the countries of Brazil, Colombia, Ecuador, Guyana, Peru and Venezuela.
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 / 29.8 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 × 15 in (roughly 36 US gallons); space needed is rated “large tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 72–81 °F, pH 6–7.5, 5–20 dGH.
- Behaviour: a shoaling fish best kept in a group of six or more.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “The species is quite shy and retiring, and needs plenty of cover in its tank.”
- Diet: “Newly imported fish tend to be quite fussy and will only accept small foods, such as bloodworm, Daphnia or granulated dried varieties.”
- Tankmates: “Despite its size, it is not a predator and is safe with all but the tiniest of fish.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Thorny catfish
Applies to most species in this group. Habitat: South American doradids include nocturnal Raphael catfish sheltering among roots and vegetation in sluggish tributaries, creeks and swamps. [fg181-raph]. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- For Platydoras armatulus, provide at least 120 × 30 × 30 cm; this minimum does not house giant doradids.
- Use subdued lighting and numerous roomy wood, pot or pipe refuges.
- Deliver sinking food after lights-out to reach hidden fish.
- Oxydoras niger needs very large accommodation and adult-sized drainpipe or wood shelters.
- Guard heaters against resting fish, particularly large Oxydoras.
Climate & lighting
| Water | 75.2–86°F |
Diet
- Sinking catfish pellets or tablets.
- Frozen bloodworms.
- Earthworms.
- Chopped mussel for larger Oxydoras.
Social life
- Platydoras armatulus tolerates its own kind and may share shelters; Oxydoras is also generally peaceful. Choose companions too large to swallow.
Handling
- Avoid mesh entanglement when transferring spiny doradids; protect yourself from sharp pectoral spines and lateral scutes.
Health watch
- Heater-contact burns in large sheltering catfish.
- Ammonia-related gill injury in poorly maintained systems.
- Skin parasites and secondary bacterial infections; general aquarium-fish risks.
Understanding the animal
About this animal
About this animal
It is found in the Orinoco and Essequibo River basins.
Quoted from the Wikipedia article “Hassar orestis” (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. Stays near the bottom. |
| Water it lives in | Freshwater. |
| Climate | Tropical climate. |
Native climate (measured)
Native climate (measured)
| Warm-season highs | about 91°F (up to 96°F in the hottest sampled areas) |
| Cool-season lows | about 70°F (down to 68°F in the coldest sampled areas) |
| Average temperature | 78–82°F across sampled records |
| Relative humidity | 75–84% on average (driest month about 75%) |
| Rainfall | about 2206 mm a year |
Measured at 80 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 |
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; aim for the middle.
pH
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 47 × 15 in (about 36 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: Platydoras armatulus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- ScotCat: Oxydoras niger factsheet 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.
- 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.
More thorny catfish
Giant Talking Catfish
Megalodoras uranoscopus
Aquarium hobby
Marbled Talking Catfish
Amblydoras nauticus
Aquarium hobby
Ripsaw catfish
Oxydoras niger
Aquarium hobby
Striped Raphael catfish
Platydoras armatulus
Aquarium hobby
Whitebarred catfish
Agamyxis pectinifrons
Aquarium hobby
Leptodoras linnelli
Leptodoras linnelli
Aquarium hobby