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Marbled Talking Catfish

Amblydoras nauticus

Fishes › Catfish (Siluriformes) › Doradidae (Thorny catfish)

Amblydoras nauticus, the marbled talking catfish or marbled raphael catfish, is a species of thorny catfish endemic to Peru where it is found in the upper Amazon basin.

Aquarium hobby
Experience: Advanced
Marbled Talking Catfish
Photo: (c) Michael Bakker Paiva, some rights reserved (CC BY), CC BY 4.0, via iNaturalist
FamilyThorny catfish
Adult lengthup to 4.4 in
WaterFreshwater
HabitatLives in freshwater. Stays near the bottom

Care at a glance

Species-specific aquarium care

  • Tank: At least 24 in long and 12 in front to back for one adult (adults commonly reach about 4.4 in / 11.1 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 24 × 12 in (roughly 14 US gallons); space needed is rated “modest tank”.
  • Water: a fairly wide range, from slightly acidic to slightly alkaline, 73–82 °F, pH 5.5–7.5, 2–20 dGH.
  • Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more.
  • Difficulty: Easy (Seriously Fish rating).

Short excerpts from the species profile:

  • Setup: “Keep it in a densely planted tank with an abundance of hiding places and dim lighting.”
  • Diet: “Proprietory catfish pellets, algae wafers and granular varieties will all be accepted, but live and frozen foods should also form a regular part of the diet.”
  • Tankmates: “Peaceful, but may eat very small fishes.”
  • Breeding: “Not yet achieved in captivity.”

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

Group care guide

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.

The water range is for P. armatulus; ScotCat gives 69.8–75.2°F for O. niger, which can exceed 90 cm. No numeric Oxydoras enclosure minimum is given by that source. P. costatus is a separate species. Individual protocols for Megalodoras uranoscopus, Agamyxis pectinifrons, A. albomaculatus, Hassar orestis and Acanthodoras cataphractus are not established here; do not use the Raphael minimum indiscriminately. Sharp armor makes transfers hazardous. Level 4 is an editorial rating reflecting giant members; P. armatulus is easier. [fg181-raph, fg181-oxy]

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.

Sources 952953954

Climate & lighting

Water75.2–86°F

Sources 952953954

Diet

  • Sinking catfish pellets or tablets.
  • Frozen bloodworms.
  • Earthworms.
  • Chopped mussel for larger Oxydoras.

Sources 952953954

Social life

  • Platydoras armatulus tolerates its own kind and may share shelters; Oxydoras is also generally peaceful. Choose companions too large to swallow.

Sources 952953954

Handling

  • Avoid mesh entanglement when transferring spiny doradids; protect yourself from sharp pectoral spines and lateral scutes.

Sources 952953954

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.

Sources 952953954

Understanding the animal

This species is part of a group that hobbyists, aviculturists or zoos keep widely (Thorny 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.
About this animal

About this animal

This species grows to a length of 7.5 centimetres (3.0 in) SL. It is often found in the aquarium trade where commonly mislabelled as "'Amblydoras hancockii" (a synonym of another species, Platydoras hancockii).

Quoted from the Wikipedia article “Amblydoras nauticus” (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.
Water it lives inFreshwater.
ClimateTropical climate.
  1. FishBase species summary: Amblydoras nauticus
Native climate (measured)

Native climate (measured)

Warm-season highsabout 89°F (up to 92°F in the hottest sampled areas)
Cool-season lowsabout 68°F (down to 68°F in the coldest sampled areas)
Average temperature78–80°F across sampled records
Relative humidity83–85% on average (driest month about 81%)
Rainfallabout 2770 mm a year, spread fairly evenly

Measured at 22 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.

OverviewAmblydoras nauticus, the marbled talking catfish or marbled raphael catfish, is a species of thorny catfish endemic to Peru where it is found in the upper Amazon basin. This species grows to a length of 7.5 cm SL. It is often found in the aquarium trade where commonly mislabelled as "Amblydoras hancockii" (a synonym of another species, Platydoras hancockii). — 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

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

Reported35g
FishBase 16435

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

Adult length

Average of sources3.7in
FishBase 1644.4
Seriously Fish species profiles 1673

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

Reported73–82°F
Seriously Fish species profiles 16773–82

Range the species tolerates; aim for the middle.

pH

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

Water hardness

Reported2–20dGH
Seriously Fish species profiles 1672–20

Minimum tank footprint

Reported24in
Seriously Fish species profiles 16724

Seriously Fish recommends a tank base of at least 24 × 12 in (about 14 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: Platydoras armatulus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  4. ScotCat: Oxydoras niger factsheet 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.