Can Golden Wonder Killifish and Masked Julie (Julidochromis) Live Together?

🔴Not Recommended

Golden Wonder Killifish 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

Golden Wonder Killifish

Aplocheilus lineatus

Masked Julie (Julidochromis)

Julidochromis transcriptus

🐠Family Group
Golden Wonder Killifish
Killifish
Masked Julie (Julidochromis)
Cichlids - African
Temperament
Golden Wonder Killifish
Semi-Aggressive (6/10)
Masked Julie (Julidochromis)
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Golden Wonder Killifish
22–28°C
Masked Julie (Julidochromis)
23–27°C
pH Range
✗ No overlap
Golden Wonder Killifish
6–7.5
Masked Julie (Julidochromis)
8–9
Hardness (dGH)
✓ Compatible
Golden Wonder Killifish
5–20
Masked Julie (Julidochromis)
10–20
Water Type
✓ Compatible
Golden Wonder Killifish
Brackish Tolerant
Masked Julie (Julidochromis)
Freshwater Only
Flow Preference
✓ Compatible
Golden Wonder Killifish
Low
Masked Julie (Julidochromis)
Moderate
Min Tank Volume
Combined: 90 L
Golden Wonder Killifish
75 L
Masked Julie (Julidochromis)
60 L
Swimming Level
✓ Different zones
Golden Wonder Killifish
Top
Masked Julie (Julidochromis)
BottomMiddle
🏷️Behavior Tags
Golden Wonder Killifish
Piscivore (Eats small/nano fish)Jumper (Lid Required)Shrimp EaterFry PredatorHyperactive / Fast Swimmer
Masked Julie (Julidochromis)
Territorial (Defends specific area)Aggressive to same species/look-alikesFry PredatorShy / Slow Moving (Easily Stressed)

Behaviour & Temperament

Both Golden Wonder Killifish and Masked Julie (Julidochromis) are moderately assertive species with an aggression score of 6/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

In terms of spatial distribution, Golden Wonder Killifish 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.

Worth noting: Golden Wonder Killifish 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 Golden Wonder Killifish (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 10–20 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Golden Wonder Killifish and Masked Julie (Julidochromis) together, plan for an aquarium of at least 90 litres with a minimum length of 60 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: Plants - Floating, Sand (Sifters). Meeting these requirements will help both species thrive.

Both species do well with low (still water) 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 Golden Wonder Killifish 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 Golden Wonder Killifish and Masked Julie (Julidochromis) need?

A minimum of 90 litres (tank length at least 60 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 Golden Wonder Killifish 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 Golden Wonder Killifish or Masked Julie (Julidochromis) aggressive?

Golden Wonder Killifish is moderately assertive (6/10) and Masked Julie (Julidochromis) is moderately assertive (6/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Golden Wonder Killifish and Masked Julie (Julidochromis) need?

Their pH requirements do not overlap. Golden Wonder Killifish prefers 6–7.5, 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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