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Black-spotted Synodontis

Synodontis acanthomias

Fishes › Catfish (Siluriformes) › Mochokidae (Synodontis and squeaker catfish)

Synodontis acanthomias is a species of upside-down catfish native to the Congo Basin of Cameroon, the Central African Republic, the Democratic Republic of the Congo and the Republic of the Congo.

Aquarium hobby
Experience: Intermediate
FamilySynodontis and squeaker catfish
Adult lengthup to 23.2 in
WaterFreshwater

Care at a glance

Species-specific aquarium care

  • Tank: At least 114 in long and 45 in front to back for one adult (adults commonly reach about 23.2 in / 59 cm).
  • Water: Freshwater.
  • Temperature: 72–75°F (range recorded for this species).
  • pH: 6.5–8.
  • Hardness: 0–25 dGH.
  • Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
  • 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 × 24 in (roughly 114 US gallons); space needed is rated “large tank”.
  • Water: a fairly wide range, from slightly acidic to slightly alkaline, 72–75 °F, pH 6.5–8, 5–25 dGH.
  • Behaviour: temperament fights its own.
  • Difficulty: Moderate (Seriously Fish rating).

Short excerpts from the species profile:

  • Setup: “A dimly lit aquarium with a soft substrate and rocks, pieces of driftwood and twisted roots arranged to form hiding places suits this species.”
  • Tankmates: “This is a very robust species and should be kept only with tankmates that can stand their own ground such as large Central American and African cichlids, large characins and barbs and Loricariids.”

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

Group care guide

Synodontis and squeaker catfish

Applies to most species in this group. Habitat: African mochokids include Synodontis from vegetated riverbanks and distinct species from rocky habitats in the East African Rift lakes. Individual species can differ, so compare with the species numbers above and the linked sources.

The water range is sourced for S. nigriventris and S. petricola, not every mochokid. Rift-lake species require separate chemistry research rather than a universal soft-water river regime. Eupterus, decorus and nigrita should not inherit the small upside-down catfish tank size. Nigrita and other larger species are sometimes mis-sold as nigriventris. These sources do not establish individual adult housing dimensions for all the listed species, including multipunctatus, njassae and polli.

Housing & setup

  • For a small S. nigriventris group, provide at least 75 × 30 × 30 cm (30 × 12 × 12 in), about 70 litres; larger species need more space.
  • Use sand or another soft substrate to protect sensitive barbels.
  • Provide plentiful daytime shelters: wood and roots for river species, rock caves for Rift-lake species.
  • For S. nigriventris, use dim lighting and broad-leaved or floating vegetation with sheltered undersides for inverted resting.
  • Separate water-chemistry plans: S. nigriventris is listed at pH 6.0–7.5 and 5–20 dGH; S. petricola at pH 7.5–8.5 and 10–35 dGH.

Sources 895896897898

Climate & lighting

Water75–82°F

Sources 895896897898

Diet

  • Complete dried foods appropriate to adult size.
  • Live or frozen aquatic foods as part of an omnivorous diet.
  • Shelled peas or cucumber; S. nigriventris may also feed inverted at the surface.

Sources 895896897898

Social life

  • Keep S. nigriventris in groups of at least three or four and S. petricola in groups of four or more. Larger Synodontis can be territorial toward other catfish and eat small tankmates; provide separate shelters and ample space.

Sources 895896897898

Health watch

  • Barbel damage associated with abrasive substrate.
  • Ammonia-related illness in poorly maintained systems.
  • Nutritional deficiencies from an unbalanced diet.

Sources 895896897898

Understanding the animal

This species is part of a group that hobbyists, aviculturists or zoos keep widely (Synodontis and squeaker 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

It was originally discovered by George Albert Boulenger in 1899 in Boma, in the Democratic Republic of the Congo. The original specimen resides in the Natural History Museum in London.

Quoted from the Wikipedia article “Synodontis acanthomias” (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. Uses both the bottom and open water.
Water it lives inFreshwater, 72–75 °F (22–24 °C), pH 6.5–8, hardness 25 dH.
ClimateTropical climate.
Behavior to plan forBreeding: open water/substratum egg scatterers.

What this means for care

  • Keep water within its wild range, 72–75 °F.
  1. FishBase species summary: Synodontis acanthomias
Native climate (measured)

Native climate (measured)

Warm-season highsabout 88°F (up to 92°F in the hottest sampled areas)
Cool-season lowsabout 64°F (down to 62°F in the coldest sampled areas)
Average temperature75–77°F across sampled records
Relative humidity73–79% on average (driest month about 69%)
Rainfallabout 1579 mm a year

Measured at 44 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.

OverviewSynodontis acanthomias is a species of upside-down catfish native to the Congo Basin of Cameroon, the Central African Republic, the Democratic Republic of the Congo and the Republic of the Congo. It was originally discovered by George Albert Boulenger in 1899 in Boma, in the Democratic Republic of the Congo. The original specimen resides in the Natural History Museum in London. The species Synodontis pfefferi, described by Franz Steindachner in 1912 was found to be the same species. — 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
ReproductionDistinct pairing during breeding. — 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

Average of sources17.5in
FishBase 16423.2
Seriously Fish species profiles 16711.8

Maximum recorded length. Measured as total length. Fish in home aquariums often stay smaller than wild records.

Water temperature

Average of sources72–75°F
FishBase 16472–75
Seriously Fish species profiles 16772–75

Range the species tolerates in nature; aim for the middle.

pH

Average of sources6.5–8
FishBase 1646.5–8
Seriously Fish species profiles 1676.5–8

Water hardness

Reported5–25dGH
Seriously Fish species profiles 1675–25

Minimum tank footprint

Reported47in
Seriously Fish species profiles 16747

Seriously Fish recommends a tank base of at least 47 × 24 in (about 114 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 — synodontis nigriventris Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  4. Seriously Fish — synodontis petricola Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  5. Practical Fishkeeping — Frequently asked questions on Synodontis Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  6. Merck Veterinary Manual — Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
  7. Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.