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Convict julie

Julidochromis regani

Also known as Regani

Fishes › Cichlids (Cichliformes) › Cichlidae (Cichlids)

The convict julie (Julidochromis regani) is a cichlid species in the subfamily Pseudocrenilabrinae family endemic to Lake Tanganyika.

Aquarium hobby
Experience: Intermediate
Convict julie
Photo: Regani, Public domain, via Wikimedia Commons
FamilyCichlids
Adult lengthup to 11.8 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 5.1 in / 13 cm).
  • Water: Freshwater.
  • Temperature: 72–77°F (range recorded for this species).
  • pH: 8.5–9.2.
  • Hardness: 8–14 dGH.
  • Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
  • Diet: FishBase classes it as a carnivore.

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: hard, alkaline water, 73–81 °F, pH 7.5–9, 10–25 dGH.
  • Behaviour: temperament territorial; in a pair.
  • Difficulty: Moderate (Seriously Fish rating).

Short excerpts from the species profile:

  • Setup: “Should be housed in a Lake Tanganyika biotope setup, with piles of rocks arranged to form caves and areas of open water between.”
  • Diet: “Live and frozen foods should comprise a large proportion of the diet.”
  • Tankmates: “Territorial but can be maintained successfully with other Tanganyikan cichlids such as Altolamprologus and Cyprichromis species.”
  • Breeding: “Easy but patience is required.”

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

Group care guide

Lake Tanganyika cichlids

Applies to most species in this group. Habitat: Rocky reefs, shell beds and sand of Lake Tanganyika. Individual species can differ, so compare with the species numbers above and the linked sources.

Housing & setup

  • Use species-specific alkaline-water parameters and stable, well-oxygenated conditions. For N. multifasciatus, Seriously Fish gives pH 7.5–9.0 and general hardness 8–25 dGH.
  • Shell-dwellers need beds of empty snail shells; rock-dwellers like Julidochromis need stacked rockwork; Tropheus need large groups and spacious tanks.

Sources 117119164118256273

Climate & lighting

Water76–81°F

Sources 117119164118256273

Diet

  • Tropheus moorii needs a vegetable-based staple with small suitable live/frozen supplements. Other Tanganyikans need their own feeding plan; shell-dweller and predator diets differ.

Sources 117119164118256273

Social life

  • Often pair- or colony-forming and territorial; research each genus.

Sources 117119164118256273

Health watch

  • Tropheus are prone to bloat on rich foods; sudden water changes stress Tanganyikans.

Sources 117119164118256273

Understanding the animal

About this animal

About this animal

Hence it is found in Burundi, the Democratic Republic of the Congo, Tanzania, and Zambia. The fish is named after Charles Tate Regan.

Quoted from the Wikipedia article “Convict julie” (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, in lakes. Uses both the bottom and open water. Likes to live in the open and ventures quite a lot over sand in the shallows.
Ground it lives onOver rock.
Water it lives inFreshwater, 72–77 °F (22–25 °C), pH 8.5–9.2, hardness 8–14 dH.
ClimateTropical climate.
Behavior to plan forBreeding: nesters.

What this means for care

  • Keep water within its wild range, 72–77 °F.
  • Provide rockwork with crevices to hide in.
  1. FishBase species summary: Julidochromis regani
Native climate (measured)

Native climate (measured)

Warm-season highsabout 85°F (up to 91°F in the hottest sampled areas)
Cool-season lowsabout 61°F (down to 54°F in the coldest sampled areas)
Average temperature68–79°F across sampled records
Relative humidity61–72% on average (driest month about 58%)
Rainfallabout 1055 mm a year

Measured at 21 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.

OverviewThe convict julie (Julidochromis regani) is a cichlid species in the subfamily Pseudocrenilabrinae family endemic to Lake Tanganyika. Hence it is found in Burundi, the Democratic Republic of the Congo, Tanzania, and Zambia. The fish is named after Charles Tate Regan. This species is closely related to Julidochromis marlieri. — 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 sizeJulidochromis regani is a small (up to 13 cm TL) ray-finned fish. Its pale to golden yellow body is slender and elongated. A varying black stripe pattern, depending on which part of the lake the fish originates from, is present. — Wikipedia (community-edited)
BiologyLikes to live in the open and ventures quite a lot over sand in the shallows. — 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 sources8.4in
FishBase 1645.1
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 sources72.5–79°F
FishBase 16472–77
Seriously Fish species profiles 16773–81

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

pH

Average of sources8–9.1
FishBase 1648.5–9.2
Seriously Fish species profiles 1677.5–9

Water hardness

Average of sources9–19.5dGH
FishBase 1648–14
Seriously Fish species profiles 16710–25

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. Merck Veterinary Manual: Management of aquarium fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
  4. Merck Veterinary Manual: Types and features of aquatic systems Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
  5. Merck Veterinary Manual: Nutritional diseases of fish Zoo, university or veterinaryThe Merck Veterinary Manual: a standard veterinary reference written and reviewed by veterinary specialists.
  6. Seriously Fish — Neolamprologus multifasciatus Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
  7. Seriously Fish — Tropheus moorii Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
  8. Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
  9. 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.