Masked Julie (Julidochromis)

Julidochromis transcriptus

Cichlids - African

The Masked Julie is the smallest species in the Julidochromis genus, endemic to the rocky shorelines of Lake Tanganyika. They are torpedo-shaped, crevice-dwelling cichlids with striking black and white checkerboard patterns. While generally peaceful toward other species that occupy different water columns, they are highly territorial and violently aggressive toward their own kind once a monogamous breeding pair is established.

At a Glance

Adult Size7 cm
Body ShapeFusiform
Growth RateSlow
TemperamentSemi-Aggressive
Water TypeFreshwater Only
Flow PreferenceModerate
Waste OutputHigh
StockingSolo or group

Tank Requirements

Minimum Volume60 L
Minimum Length60 cm
FlowModerate
Water TypeFreshwater Only
Must-Haves in the Tank
Sand (Sifters)

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Water Parameters

Temperature2327°C
pH89
Hardness1020 dGH

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Temperament & Compatibility

Aggression LevelSemi-Aggressive
6/10
Where They Swim
Surface
Mid-level
Bottom
Stocking Guidelines
Keep at Least1 (solo is fine)
Max per Tank2
Can Live Alone?Yes
Behavior Traits
Territorial (Defends specific area)Aggressive to same species/look-alikesFry PredatorShy / Slow Moving (Easily Stressed)

Available Varieties

Each variety inherits the species defaults above. Only differences are highlighted.

Standard

The standard wild-type form. Usually purchased in a group of 6 juveniles to allow a natural pair to form, after which the remaining unpaired fish must be removed to prevent them from being killed by the dominant pair.

Same care requirements as the base species

Also known as: Gombi, Kissi, Pemba

Masked Julie (Julidochromis) Care Guide Summary

The Masked Julie (Julidochromis), scientifically known as Julidochromis transcriptus, belongs to the Cichlids - African family group. Adults reach a maximum size of approximately 7 cm and have a fusiform body shape with a slow growth rate. Classified as semi-aggressive, this species primarily occupies the bottom and mid-level zones of the aquarium and produces a high level of biological waste.

To thrive, the Masked Julie (Julidochromis) requires a freshwater only aquarium with a minimum volume of 60 litres and a tank length of at least 60 cm. Water temperature should be maintained between 23°C and 27°C, with a pH range of 89 and a general hardness of 1020 dGH. A moderate water flow is preferred. An aquarium test kit can help you monitor these values.

The Masked Julie (Julidochromis) is a rewarding species to keep, provided its core environmental needs are met. The Masked Julie (Julidochromis) is typically available in one standard form.

Masked Julie (Julidochromis) Habitat Setup

When setting up an aquarium for the Masked Julie (Julidochromis), a moderate water flow best suits their natural preferences. Because this species occupies the bottom and mid-level zones, the aquarium layout should prioritise open swimming space in the centre of the tank for free movement and sufficient floor space with hiding spots among rocks, wood, or dense planting. Useful additions include a sand substrate to accommodate their sifting behaviour. Browse aquarium sand substrate options to find the best fit.

Masked Julie (Julidochromis) Compatibility Notes

Classified as semi-aggressive, the Masked Julie (Julidochromis) is adaptable and can be kept singly or in a small group, offering flexibility when planning a community tank. When choosing tankmates, conspecific aggression can be intense, especially in smaller tanks, territorial behaviour may cause issues if hiding spots or floor space are limited, and boisterous or fast-moving tankmates may cause this species undue stress. Selecting tankmates that favour different water layers from the bottom and mid-level zones can help reduce competition and territorial overlap.

Frequently Asked Questions About Masked Julie (Julidochromis)

How big does Masked Julie (Julidochromis) get?+
Masked Julie (Julidochromis) (Julidochromis transcriptus) typically reaches a maximum adult size of approximately 7 cm. They have a fusiform body shape and a slow growth rate.
What tank size does Masked Julie (Julidochromis) need?+
A minimum aquarium volume of 60 litres and a tank length of at least 60 cm are recommended for Masked Julie (Julidochromis). This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Masked Julie (Julidochromis) need?+
Masked Julie (Julidochromis) thrives in freshwater only conditions with a temperature range of 23–27°C, a pH between 8 and 9, and a general hardness of 10–20 dGH. A moderate water flow is preferred.
Is Masked Julie (Julidochromis) peaceful or aggressive?+
Masked Julie (Julidochromis) is classified as semi-aggressive with an aggression score of 6 out of 10. They can work in community setups but may clash with certain tankmates.
Can Masked Julie (Julidochromis) live alone?+
Yes, Masked Julie (Julidochromis) can be kept singly or in a group. They are flexible and adapt well to both setups.
Does Masked Julie (Julidochromis) have any special tank requirements?+
Yes. Masked Julie (Julidochromis) benefits from sand (sifters) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.

Similar Species

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Julii Corydoras (False Julii)

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Catfish
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Often sold in the aquarium trade as the 'Julii Cory', the False Julii (Corydoras trilineatus) is a peaceful, highly social bottom-dweller. It features a distinct reticulated (maze-like) pattern on its head and a prominent horizontal stripe down its body. As an obligate schooling fish, it must be kept in groups to thrive and feel secure. A soft sand substrate is absolutely critical to prevent the erosion of their sensitive foraging barbels.