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No federal permit to keep

Blue Diamond Characin

Alestopetersius smykalai

Also known as Blue Diamond Tetra

Fishes › Tetras, piranhas and pacus (Characiformes) › Alestidae (African tetras)

Alestopetersius smykalai is a species of freshwater ray-finned fish belonging to the family Alestidae, the African tetras.

Aquarium hobby
Experience: Advanced
FamilyAfrican tetras
Adult lengthup to 2.4 in
WaterFreshwater
HabitatLives in freshwater

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 2.4 in / 6 cm).
  • Water: Freshwater.
  • Temperature: 73–81°F (range recorded for this species).
  • pH: 6–7.2.
  • Hardness: 8–15 dGH.
  • Layout: An open-water swimmer: needs long, open swimming space with few obstacles.
  • 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 × 12 in (roughly 29 US gallons); space needed is rated “large tank”.
  • Water: soft, acidic water, 68–82 °F, pH 5–7, 1–10 dGH.
  • Behaviour: temperament peaceful; a shoaling fish best kept in a group of six or more; suited to a community tank.
  • Difficulty: Easy (Seriously Fish rating).

Short excerpts from the species profile:

  • Setup: “Décor is relatively unimportant and this species will do well in planted aquaria but ideally the aquarium should ideally be designed to resemble a flowing stream or river with a substrate of variably-sized rocks, sand, fine gravel, and some larger water-worn…”
  • Diet: “Wild fish are probably foragers feeding on small insects, crustaceans, fallen fruit, etc.”
  • Tankmates: “Lively and somewhat skittish but generally peaceful making it an ideal resident of the well-researched, larger community aquarium.”
  • Breeding: “Has not been bred with any regularity in the aquarium hobby and few details are available.”

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

Group care guide

African tetras

Applies to most species in this group. Habitat: African freshwater habitats range from the Congo drainage occupied by Congo tetras to large rivers and lakes inhabited by giant tigerfish. Individual species can differ, so compare with the species numbers above and the linked sources.

Level 4 is an editorial family rating; Congo tetras are intermediate aquarium fish, while H. goliath is level 5, facility only, with dangerous interlocking teeth. Temperature applies to Congo tetras; giant tigerfish are sourced at 75.2–82.4°F. The approximate 15,000-litre figure is not a validated universal minimum. Do not apply Congo-tetra housing or diet to H. vittatus or H. forskahlii. Bryconalestes, Alestopetersius, P. aurantiacus and Alestes also require species-specific checks.

Housing & setup

  • Adult Congo tetras need at least 120 × 30 × 30 cm (about 48 × 12 × 12 inches).
  • For Congo tetras, combine plants, floating vegetation and driftwood with open swimming space and good circulation.
  • Congo-tetra source parameters are pH 6.0–7.5 and hardness 3–18 dGH; maintain consistently high water quality.
  • Hydrocynus goliath needs a facility-scale system: the source suggests roughly 15,000 litres rather than a home aquarium.
  • For giant tigerfish, prioritize oxygenation, clean water and open swimming space with minimal hard decor.

Sources 929930931

Climate & lighting

Water73.4–82.4°F

Sources 929930931

Diet

  • For Congo tetras: suitable dried omnivore foods including algae-based foods.
  • For Congo tetras: small live or frozen worms, insects and crustaceans.
  • For tigerfish: appropriately sized dead fish such as whitebait.

Sources 929930931

Social life

  • Congo tetras suit mixed-sex shoals with peaceful companions; fin-nippers damage male fins. Adult giant tigerfish should be kept alone and may attack smaller fish without warning.

Sources 929930931

Handling

  • Giant tigerfish require professional separation and maintenance procedures because adults pose a serious bite hazard.

Sources 929930931

Health watch

  • Ammonia toxicity.
  • Nutritional deficiencies.

Sources 929930931

Understanding the animal

This species is part of a group that hobbyists, aviculturists or zoos keep widely (African tetras), 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 is found in the lower Niger River.

Quoted from the Wikipedia article “Alestopetersius smykalai” (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.
Water it lives inFreshwater, 73–81 °F (23–27 °C), pH 6–7.2, hardness 8–15 dH.
ClimateTropical climate.

What this means for care

  • Keep water within its wild range, 73–81 °F.
  1. FishBase species summary: Alestopetersius smykalai
Native climate (measured)

Native climate (measured)

Warm-season highsabout 91°F (up to 91°F in the hottest sampled areas)
Cool-season lowsabout 70°F (down to 69°F in the coldest sampled areas)
Average temperature79–80°F across sampled records
Relative humidity82–83% on average (driest month about 78%)
Rainfallabout 2454 mm a year

Measured at 6 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.

OverviewAlestopetersius smykalai is a species of freshwater ray-finned fish belonging to the family Alestidae, the African tetras. It is found in the lower Niger River. — 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 sizeAlestopetersius smykalai reaches a total length of 6.0 cm. — Wikipedia (community-edited)
History and namingThe tetra is named in honor of E. R. Smykala, who procured the original specimen. — Wikipedia (community-edited)

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 sources2.4in
FishBase 1642.4
Seriously Fish species profiles 1672.4

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

Water temperature

Average of sources70.5–81.5°F
FishBase 16473–81
Seriously Fish species profiles 16768–82

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

pH

Average of sources5.5–7.1
FishBase 1646–7.2
Seriously Fish species profiles 1675–7

Water hardness

Average of sources4.5–12.5dGH
FishBase 1648–15
Seriously Fish species profiles 1671–10

Minimum tank footprint

Reported47in
Seriously Fish species profiles 16747

Seriously Fish recommends a tank base of at least 47 × 12 in (about 29 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 — Phenacogrammus interruptus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
  4. Seriously Fish — Hydrocynus goliath 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.