Can Iridescent Shark and Masked Julie (Julidochromis) Live Together?

🔴Not Recommended

Iridescent Shark and Masked Julie (Julidochromis) are not recommended as tank mates due to conflicting pH requirements. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Iridescent Shark

Pangasianodon hypophthalmus

Masked Julie (Julidochromis)

Julidochromis transcriptus

🐠Family Group
Iridescent Shark
Catfish
Masked Julie (Julidochromis)
Cichlids - African
Temperament
Iridescent Shark
Mostly Peaceful (3/10)
Masked Julie (Julidochromis)
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Iridescent Shark
22–28°C
Masked Julie (Julidochromis)
23–27°C
pH Range
✗ No overlap
Iridescent Shark
6.5–7.5
Masked Julie (Julidochromis)
8–9
Hardness (dGH)
✓ Compatible
Iridescent Shark
2–20
Masked Julie (Julidochromis)
10–20
Water Type
✓ Compatible
Iridescent Shark
Freshwater Only
Masked Julie (Julidochromis)
Freshwater Only
Flow Preference
✓ Compatible
Iridescent Shark
Moderate
Masked Julie (Julidochromis)
Moderate
Min Tank Volume
Combined: 2400 L
Iridescent Shark
2000 L
Masked Julie (Julidochromis)
60 L
Swimming Level
Shared: 1 zone
Iridescent Shark
Middle
Masked Julie (Julidochromis)
BottomMiddle
🏷️Behavior Tags
Iridescent Shark
Piscivore (Eats small/nano fish)Hyperactive / Fast SwimmerJumper (Lid Required)Shy / Slow Moving (Easily Stressed)
Masked Julie (Julidochromis)
Territorial (Defends specific area)Aggressive to same species/look-alikesFry PredatorShy / Slow Moving (Easily Stressed)

Behaviour & Temperament

Iridescent Shark is a generally mild-mannered species (3/10), while Masked Julie (Julidochromis) is moderately assertive (6/10). This modest difference means Masked Julie (Julidochromis) may occasionally assert dominance over Iridescent Shark.

Iridescent Shark and Masked Julie (Julidochromis) both frequent the Middle (Open Water) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Iridescent Shark is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 23°C and 27°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

The pH requirements of Iridescent Shark (6.5–7.5) and Masked Julie (Julidochromis) (8–9) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 10–20 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Iridescent Shark and Masked Julie (Julidochromis) together, plan for an aquarium of at least 2400 litres with a minimum length of 250 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

Providing a mix of open swimming space and sheltered areas with rocks, driftwood, or plants will keep both species comfortable and allow natural behaviour.

Specific environmental needs for this combination include: Smooth Gravel (Sensitive Barbels), Sand (Sifters). Meeting these requirements will help both species thrive.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

Find the right tank equipment

Browse tanks, décor, and equipment suited for this setup.

Frequently Asked Questions

Can Iridescent Shark and Masked Julie (Julidochromis) live together?

No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.

What size tank do Iridescent Shark and Masked Julie (Julidochromis) need?

A minimum of 2400 litres (tank length at least 250 cm) is recommended. This provides enough space for both species to establish their own areas and reduces the likelihood of territorial disputes.

What water temperature is best for Iridescent Shark and Masked Julie (Julidochromis) together?

Keep the aquarium between 23°C and 27°C. A target of around 25.0°C sits comfortably within both species' preferred ranges.

Are Iridescent Shark or Masked Julie (Julidochromis) aggressive?

Iridescent Shark is generally mild-mannered (3/10) and Masked Julie (Julidochromis) is moderately assertive (6/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Iridescent Shark and Masked Julie (Julidochromis) need?

Their pH requirements do not overlap. Iridescent Shark prefers 6.5–7.5, while Masked Julie (Julidochromis) needs 8–9. This makes them incompatible in the same water chemistry.

How do I manage Masked Julie (Julidochromis)'s territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Masked Julie (Julidochromis) space to claim a territory without encroaching on the other fish's area. Adding décor that divides the tank into distinct zones works especially well.


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