Can Flagtail Cory (Mrs Schwartz's Cory) and Masked Julie (Julidochromis) Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 6, 2026
Not Recommended

Flagtail Cory (Mrs Schwartz's Cory) 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

Flagtail Cory (Mrs Schwartz's Cory)

Corydoras robineae

Masked Julie (Julidochromis)

Julidochromis transcriptus

🐠Family Group
Flagtail Cory (Mrs Schwartz's Cory)
Catfish
Masked Julie (Julidochromis)
Cichlids - African
Temperament
Flagtail Cory (Mrs Schwartz's Cory)
Peaceful (1/10)
Masked Julie (Julidochromis)
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Flagtail Cory (Mrs Schwartz's Cory)
24–28°C
Masked Julie (Julidochromis)
23–27°C
pH Range
✗ No overlap
Flagtail Cory (Mrs Schwartz's Cory)
6–7.5
Masked Julie (Julidochromis)
8–9
Hardness (dGH)
✓ Compatible
Flagtail Cory (Mrs Schwartz's Cory)
2–12
Masked Julie (Julidochromis)
10–20
Water Type
✓ Compatible
Flagtail Cory (Mrs Schwartz's Cory)
Freshwater Only
Masked Julie (Julidochromis)
Freshwater Only
Flow Preference
✓ Compatible
Flagtail Cory (Mrs Schwartz's Cory)
Moderate
Masked Julie (Julidochromis)
Moderate
Min Tank Volume
Combined: 60 L
Flagtail Cory (Mrs Schwartz's Cory)
60 L
Masked Julie (Julidochromis)
60 L
Swimming Level
Shared: 1 zone
Flagtail Cory (Mrs Schwartz's Cory)
Bottom
Masked Julie (Julidochromis)
BottomMiddle
🏷️Behavior Tags
Flagtail Cory (Mrs Schwartz's Cory)
Hyperactive / Fast SwimmerShy / Slow Moving (Easily Stressed)
Masked Julie (Julidochromis)
Territorial (Defends specific area)Aggressive to same species/look-alikesFry PredatorShy / Slow Moving (Easily Stressed)
Stocking calculator

Can your tank handle Flagtail Cory (Mrs Schwartz's Cory) 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.

Flagtail Cory (Mrs Schwartz's Cory)
Masked Julie (Julidochromis)
Test both in my tank

Behaviour & Temperament

Flagtail Cory (Mrs Schwartz's Cory) is a peaceful species (1/10), while Masked Julie (Julidochromis) is moderately assertive (6/10). This notable difference means Masked Julie (Julidochromis) may occasionally assert dominance over Flagtail Cory (Mrs Schwartz's Cory).

Flagtail Cory (Mrs Schwartz's Cory) and Masked Julie (Julidochromis) 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.

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

Water Parameters

The safe temperature window for both species falls between 24°C and 27°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

The pH requirements of Flagtail Cory (Mrs Schwartz's Cory) (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 Flagtail Cory (Mrs Schwartz's Cory) and Masked Julie (Julidochromis) together, plan for an aquarium of at least 60 litres with a minimum length of 60 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), Leaf Litter/Blackwater. 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

Flagtail Cory (Mrs Schwartz's Cory) and Masked Julie (Julidochromis) 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.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Flagtail Cory (Mrs Schwartz's Cory) and Masked Julie (Julidochromis).

Show 19 more tank sizes

Frequently Asked Questions

Can Flagtail Cory (Mrs Schwartz's Cory) 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 Flagtail Cory (Mrs Schwartz's Cory) and Masked Julie (Julidochromis) need?

A minimum of 60 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 Flagtail Cory (Mrs Schwartz's Cory) and Masked Julie (Julidochromis) together?

Keep the aquarium between 24°C and 27°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Flagtail Cory (Mrs Schwartz's Cory) or Masked Julie (Julidochromis) aggressive?

Flagtail Cory (Mrs Schwartz's Cory) is peaceful (1/10) and Masked Julie (Julidochromis) is moderately assertive (6/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Flagtail Cory (Mrs Schwartz's Cory) and Masked Julie (Julidochromis) need?

Their pH requirements do not overlap. Flagtail Cory (Mrs Schwartz's Cory) 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.

Editorial Review

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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