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Mastacembelus ellipsifer

Mastacembelus ellipsifer

Fishes › Spiny eels and swamp eels (Synbranchiformes) › Mastacembelidae (Spiny eels)

Mastacembelus ellipsifer is a species of spiny eel that is endemic to Lake Tanganyika in Africa and sometimes kept in aquariums.

Aquarium hobby
Experience: Advanced
Mastacembelus ellipsifer
Photo: The original uploader was Jtanganyika at French Wikipedia., CC BY-SA 3.0, via Wikimedia Commons
FamilySpiny eels
Adult lengthup to 17.7 in
WaterFreshwater

Care at a glance

Species-specific aquarium care

  • Tank: At least 90 in long and 36 in front to back for one adult (adults commonly reach about 17.7 in / 45 cm).
  • Water: Freshwater.
  • Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.

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 × 18 in (roughly 64 US gallons); space needed is rated “large tank”.
  • Water: hard, alkaline water, 73–81 °F, pH 8–9.5, 8–25 dGH.
  • Behaviour: temperament predatory.
  • Difficulty: Moderate (Seriously Fish rating).

Short excerpts from the species profile:

  • Setup: “Use piles of rocks to form sheltered areas.”
  • Diet: “In nature, the spiny eel preys on small fish but aquarium specimens readily accept dead alternatives.”
  • Tankmates: “Peaceful with species it cannot fit into its mouth.”
  • Breeding: “Has not been bred in the hobby.”

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

Group care guide

Spiny eels

Applies to most species in this group. Habitat: The listed Asian spiny eels inhabit freshwater rivers, backwaters and floodplains, with fire eels associated particularly with sluggish lowland water. Individual species can differ, so compare with the species numbers above and the linked sources.

Temperature is for M. erythrotaenia. Large Mastacembelus and smaller Macrognathus differ in adult housing and prey sizes. This fire-eel protocol is not verified for Sinobdella sinensis or all listed species. These are freshwater spiny fishes, not true marine eels.

Housing & setup

  • Use soft sand that permits burrowing; avoid sharp gravel.
  • Provide daytime shelters using wood, caves or appropriately sized PVC tubes.
  • Fit a close-fitting cover and seal escape gaps.
  • Use subdued lighting, floating plants and gentle flow for fire eels.
  • The fire-eel profile specifies 48 × 24 × 24 inches, about 114 US gallons, but also reports adults up to 39 inches; plan accommodation around actual adult size and enlarge accordingly.

Sources 970971972

Climate & lighting

Water75.2–82.4°F

Sources 970971972

Diet

  • Prawns and krill for large Mastacembelus.
  • Lancefish or other suitable meaty foods for large specimens.
  • Small live or frozen invertebrates for juveniles and smaller species.

Sources 970971972

Social life

  • Usually house large Mastacembelus singly; small fishes may be eaten. Smaller Macrognathus can be more sociable, but compatibility requires species-specific assessment.

Sources 970971972

Handling

  • For necessary capture use a deep soft net and prepare a deep double bag; minimize abrasion.

Sources 970971972

Health watch

  • Skin trauma from substrate or capture.
  • Bacterial skin infections.
  • Parasitic infections.

Sources 970971972

Understanding the animal

About this animal

About this animal

Although sometimes called the Tanganyikan spiny eel, it is only one of fifteen spiny eel species in the Tanganyikan basin (fourteen endemic).

Quoted from the Wikipedia article “Mastacembelus ellipsifer” (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. Inhabits coastal waters with sandy, rocky or muddy bottom.
Water it lives inFreshwater.
ClimateTropical climate.
  1. FishBase species summary: Mastacembelus ellipsifer
Native climate (measured)

Native climate (measured)

Warm-season highsabout 86°F (up to 91°F in the hottest sampled areas)
Cool-season lowsabout 59°F (down to 54°F in the coldest sampled areas)
Average temperature68–81°F across sampled records
Relative humidity54–72% on average (driest month about 57%)
Rainfallabout 1057 mm a year, with strong wet and dry seasons

Measured at 19 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.

OverviewMastacembelus ellipsifer is a species of spiny eel that is endemic to Lake Tanganyika in Africa and sometimes kept in aquariums. Although sometimes called the Tanganyikan spiny eel, it is only one of fifteen spiny eel species in the Tanganyikan basin (fourteen endemic). — 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
Appearance and sizeM. ellipsifer can up to 45 cm long. It is brown, with a darker ring-shaped pattern running down its back. Its dorsal fins are hard. — Wikipedia (community-edited)
BiologyInhabits coastal waters with sandy, rocky or muddy bottom. — 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 sources17.7in
FishBase 16417.7
Seriously Fish species profiles 16717.7

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

Water temperature

Reported73–81°F
Seriously Fish species profiles 16773–81

Range the species tolerates; aim for the middle.

pH

Reported8–9.5
Seriously Fish species profiles 1678–9.5

Water hardness

Reported8–25dGH
Seriously Fish species profiles 1678–25

Minimum tank footprint

Reported47in
Seriously Fish species profiles 16747

Seriously Fish recommends a tank base of at least 47 × 18 in (about 64 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. Mastacembelus erythrotaenia — Seriously Fish Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  4. Spiny Freshwater Eels, Family Mastacembelidae — Bob Fenner Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  5. Spiny Eel Foods and Nutrition — WetWebMedia Experienced keeper or breederAdded 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.