Can Marlier's Julie and Walking Catfish (Clarias) Live Together?
Marlier's Julie and Walking Catfish (Clarias) 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
Can your tank handle Marlier's Julie and Walking Catfish (Clarias)?
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.
Behaviour & Temperament
Marlier's Julie is a moderately assertive species (6/10), while Walking Catfish (Clarias) is semi-aggressive (8/10). This modest difference means Walking Catfish (Clarias) may occasionally assert dominance over Marlier's Julie.
Marlier's Julie and Walking Catfish (Clarias) both frequent the Bottom (Substrate) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.
Worth noting: Walking Catfish (Clarias) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Walking Catfish (Clarias) 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 Marlier's Julie (8.2–9.3) and Walking Catfish (Clarias) (5.5–8) 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.
Tank Setup
To house Marlier's Julie and Walking Catfish (Clarias) together, plan for an aquarium of at least 750 litres with a minimum length of 180 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: Sand (Sifters), Smooth Gravel (Sensitive Barbels). 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.
Why This Pairing Usually Fails in Practice
Marlier's Julie and Walking Catfish (Clarias) are the kind of pair that can look acceptable in a shop but become a maintenance problem at home. The main risk is not a single number in the chart; it is the way incompatible behavior, water needs, or pressure on space compounds over time once both fish are established in the same tank.
Frequently Asked Questions
Can Marlier's Julie and Walking Catfish (Clarias) live together?
No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.
What size tank do Marlier's Julie and Walking Catfish (Clarias) need?
A minimum of 750 litres (tank length at least 180 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 Marlier's Julie and Walking Catfish (Clarias) 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 Marlier's Julie or Walking Catfish (Clarias) aggressive?
Marlier's Julie is moderately assertive (6/10) and Walking Catfish (Clarias) is semi-aggressive (8/10). Their similar temperaments generally lead to a peaceful coexistence.
What pH do Marlier's Julie and Walking Catfish (Clarias) need?
Their pH requirements do not overlap. Marlier's Julie prefers 8.2–9.3, while Walking Catfish (Clarias) needs 5.5–8. This makes them incompatible in the same water chemistry.
How do I manage Marlier's Julie's territorial behaviour?
Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Marlier's Julie 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.
Does Walking Catfish (Clarias) being nocturnal affect compatibility?
Walking Catfish (Clarias) is most active after lights-out, which naturally reduces daytime encounters with its tank mate. This can actually be beneficial, as both fish get undisturbed time to feed and explore. Just ensure food reaches Walking Catfish (Clarias) during evening hours.
Shared setup supplies
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Guidarium Editorial Desk
Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.
- Last reviewed
- May 6, 2026
- Last updated
- May 6, 2026
- Issues or corrections?
- Contact the editorial team
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