Can Asian Arowana and Masked Julie (Julidochromis) Live Together?

Not Recommended

Asian Arowana 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

Asian Arowana

Scleropages formosus

Masked Julie (Julidochromis)

Julidochromis transcriptus

🐠Family Group
Asian Arowana
Oddballs
Masked Julie (Julidochromis)
Cichlids - African
Temperament
Asian Arowana
Aggressive (8/10)
Masked Julie (Julidochromis)
Semi-Aggressive (6/10)
Temperature
βœ“ Compatible
Asian Arowana
26–30Β°C
Masked Julie (Julidochromis)
23–27Β°C
pH Range
βœ— No overlap
Asian Arowana
6–7.5
Masked Julie (Julidochromis)
8–9
Hardness (dGH)
βœ“ Compatible
Asian Arowana
1–12
Masked Julie (Julidochromis)
10–20
Water Type
βœ“ Compatible
Asian Arowana
Freshwater Only
Masked Julie (Julidochromis)
Freshwater Only
Flow Preference
βœ“ Compatible
Asian Arowana
Moderate
Masked Julie (Julidochromis)
Moderate
Min Tank Volume
Combined: 1000 L
Asian Arowana
1000 L
Masked Julie (Julidochromis)
60 L
Swimming Level
βœ“ Different zones
Asian Arowana
Top
Masked Julie (Julidochromis)
BottomMiddle
🏷️Behavior Tags
Asian Arowana
Piscivore (Eats small/nano fish)Jumper (Lid Required)Aggressive to same species/look-alikesTerritorial (Defends specific area)Hyperactive / Fast Swimmer
Masked Julie (Julidochromis)
Territorial (Defends specific area)Aggressive to same species/look-alikesFry PredatorShy / Slow Moving (Easily Stressed)
Stocking calculator

Can your tank handle Asian Arowana and Masked Julie (Julidochromis)?

Compatibility is only part of the answer. Test both fish with your real tank size, current stock, and maintenance needs to see if you have enough space and a safe stocking level before you add them.

Asian Arowana
Masked Julie (Julidochromis)
Test both in my tank

Behaviour & Temperament

Asian Arowana is a semi-aggressive species (8/10), while Masked Julie (Julidochromis) is moderately assertive (6/10). This modest difference means Asian Arowana may occasionally assert dominance over Masked Julie (Julidochromis).

In terms of spatial distribution, Asian Arowana prefers the Top (Surface) zone, whereas Masked Julie (Julidochromis) occupies the Bottom (Substrate) and Middle (Open Water) zones. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion. Two territorial species may clash over territory, especially in smaller tanks.

Worth noting: Asian Arowana is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 26Β°C and 27Β°C. Aim for the midpoint of this range (around 26.5Β°C) for optimal comfort.

The pH requirements of Asian Arowana (6–7.5) 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 10–12 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Asian Arowana and Masked Julie (Julidochromis) together, plan for an aquarium of at least 1000 litres with a minimum length of 240 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

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.

Frequently Asked Questions

Can Asian Arowana and Masked Julie (Julidochromis) live together?

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

What size tank do Asian Arowana and Masked Julie (Julidochromis) need?

A minimum of 1000 litres (tank length at least 240 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 Asian Arowana and Masked Julie (Julidochromis) together?

Keep the aquarium between 26Β°C and 27Β°C. A target of around 26.5Β°C sits comfortably within both species' preferred ranges.

Are Asian Arowana or Masked Julie (Julidochromis) aggressive?

Asian Arowana is semi-aggressive (8/10) and Masked Julie (Julidochromis) is moderately assertive (6/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Asian Arowana and Masked Julie (Julidochromis) need?

Their pH requirements do not overlap. Asian Arowana prefers 6–7.5, while Masked Julie (Julidochromis) needs 8–9. This makes them incompatible in the same water chemistry.

How do I manage Asian Arowana's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Asian Arowana space to claim a territory without encroaching on the other fish's area. Adding dΓ©cor that divides the tank into distinct zones works especially well.


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