Can Masked Julie (Julidochromis) and Rachov's Killifish (Annual) Live Together?

🔴Not Recommended

Masked Julie (Julidochromis) and Rachov's Killifish (Annual) 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

Masked Julie (Julidochromis)

Julidochromis transcriptus

Rachov's Killifish (Annual)

Nothobranchius rachovii

🐠Family Group
Masked Julie (Julidochromis)
Cichlids - African
Rachov's Killifish (Annual)
Killifish
Temperament
Masked Julie (Julidochromis)
Semi-Aggressive (6/10)
Rachov's Killifish (Annual)
Mostly Peaceful (3/10)
Temperature
✓ Compatible
Masked Julie (Julidochromis)
23–27°C
Rachov's Killifish (Annual)
20–26°C
pH Range
✗ No overlap
Masked Julie (Julidochromis)
8–9
Rachov's Killifish (Annual)
6–7.5
Hardness (dGH)
✓ Compatible
Masked Julie (Julidochromis)
10–20
Rachov's Killifish (Annual)
4–12
Water Type
✓ Compatible
Masked Julie (Julidochromis)
Freshwater Only
Rachov's Killifish (Annual)
Freshwater Only
Flow Preference
✓ Compatible
Masked Julie (Julidochromis)
Moderate
Rachov's Killifish (Annual)
Low
Min Tank Volume
Combined: 72 L
Masked Julie (Julidochromis)
60 L
Rachov's Killifish (Annual)
19 L
Swimming Level
Shared: 2 zones
Masked Julie (Julidochromis)
BottomMiddle
Rachov's Killifish (Annual)
MiddleBottom
🏷️Behavior Tags
Masked Julie (Julidochromis)
Territorial (Defends specific area)Aggressive to same species/look-alikesFry PredatorShy / Slow Moving (Easily Stressed)
Rachov's Killifish (Annual)
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)

Behaviour & Temperament

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

Masked Julie (Julidochromis) and Rachov's Killifish (Annual) both frequent the Bottom (Substrate) and 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: Rachov's Killifish (Annual) 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 26°C. Aim for the midpoint of this range (around 24.5°C) for optimal comfort.

The pH requirements of Masked Julie (Julidochromis) (8–9) and Rachov's Killifish (Annual) (6–7.5) 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. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Masked Julie (Julidochromis) and Rachov's Killifish (Annual) together, plan for an aquarium of at least 72 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: Sand (Sifters), Soil / Nutrient Rich, Leaf Litter/Blackwater, Plants - Densely covered. Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Masked Julie (Julidochromis) requires Sand (Sifters), while Rachov's Killifish (Annual) requires Soil / Nutrient Rich. These substrate types may be difficult to provide simultaneously. Compromise where possible or prioritise the more critical need.

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 Masked Julie (Julidochromis) and Rachov's Killifish (Annual) live together?

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

What size tank do Masked Julie (Julidochromis) and Rachov's Killifish (Annual) need?

A minimum of 72 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 Masked Julie (Julidochromis) and Rachov's Killifish (Annual) together?

Keep the aquarium between 23°C and 26°C. A target of around 24.5°C sits comfortably within both species' preferred ranges.

Are Masked Julie (Julidochromis) or Rachov's Killifish (Annual) aggressive?

Masked Julie (Julidochromis) is moderately assertive (6/10) and Rachov's Killifish (Annual) is generally mild-mannered (3/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Masked Julie (Julidochromis) and Rachov's Killifish (Annual) need?

Their pH requirements do not overlap. Masked Julie (Julidochromis) prefers 8–9, while Rachov's Killifish (Annual) needs 6–7.5. 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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