Can Dusky Millions Fish and Julii Corydoras (False Julii) Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 4, 2026
Ideal Tank Mates

Yes, Dusky Millions Fish and Julii Corydoras (False Julii) are ideal tank mates. Both species share compatible water parameters and peaceful temperaments, making them well-suited for a community aquarium. They occupy different areas of the water column, which reduces competition for space. A minimum tank size of 60 litres is recommended.


At a Glance

Dusky Millions Fish

Phalloceros caudimaculatus

Julii Corydoras (False Julii)

Corydoras trilineatus

🐠Family Group
Dusky Millions Fish
Livebearers
Julii Corydoras (False Julii)
Catfish
Temperament
Dusky Millions Fish
Peaceful (2/10)
Julii Corydoras (False Julii)
Peaceful (0/10)
Temperature
✓ Compatible
Dusky Millions Fish
16–24°C
Julii Corydoras (False Julii)
22–26°C
pH Range
✓ Compatible
Dusky Millions Fish
7–8
Julii Corydoras (False Julii)
6–7.5
Hardness (dGH)
✓ Compatible
Dusky Millions Fish
8–20
Julii Corydoras (False Julii)
2–15
Water Type
✓ Compatible
Dusky Millions Fish
Brackish Tolerant
Julii Corydoras (False Julii)
Freshwater Only
Flow Preference
✓ Compatible
Dusky Millions Fish
Low
Julii Corydoras (False Julii)
Moderate
Min Tank Volume
Combined: 60 L
Dusky Millions Fish
40 L
Julii Corydoras (False Julii)
60 L
Swimming Level
✓ Different zones
Dusky Millions Fish
TopMiddle
Julii Corydoras (False Julii)
Bottom
🏷️Behavior Tags
Dusky Millions Fish
Hyperactive / Fast SwimmerPlant DestroyerFin Nipper
Julii Corydoras (False Julii)
Hyperactive / Fast Swimmer
Stocking calculator

Can your tank handle Dusky Millions Fish and Julii Corydoras (False Julii)?

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.

Dusky Millions Fish
Julii Corydoras (False Julii)
Test both in my tank

Behaviour & Temperament

Dusky Millions Fish is a peaceful species (2/10), while Julii Corydoras (False Julii) is peaceful (0/10). This modest difference means Dusky Millions Fish may occasionally assert dominance over Julii Corydoras (False Julii).

In terms of spatial distribution, Dusky Millions Fish prefers the Top (Surface) and Middle (Open Water) zones, whereas Julii Corydoras (False Julii) occupies the Bottom (Substrate) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Water Parameters

The safe temperature window for both species falls between 22°C and 24°C. Aim for the midpoint of this range (around 23.0°C) for optimal comfort.

Both fish can tolerate a pH between 7 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 8–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Dusky Millions Fish and Julii Corydoras (False Julii) 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: Plants - Densely covered, Plants - Floating, Established Algae (Otocinclus), 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.

Why This Pairing Works in Practice

Dusky Millions Fish and Julii Corydoras (False Julii) work best when the tank gives each fish enough room to use its preferred level of the aquarium and enough cover to avoid constant visual contact. The score matters, but the real-world success usually comes from matching their pace, keeping water stable, and resisting the urge to crowd the tank just because the pair looks safe on paper.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Dusky Millions Fish and Julii Corydoras (False Julii).

Show 19 more tank sizes

Frequently Asked Questions

Can Dusky Millions Fish and Julii Corydoras (False Julii) live together?

Yes. Dusky Millions Fish and Julii Corydoras (False Julii) are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.

What size tank do Dusky Millions Fish and Julii Corydoras (False Julii) 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 Dusky Millions Fish and Julii Corydoras (False Julii) together?

Keep the aquarium between 22°C and 24°C. A target of around 23.0°C sits comfortably within both species' preferred ranges.

Are Dusky Millions Fish or Julii Corydoras (False Julii) aggressive?

Dusky Millions Fish is peaceful (2/10) and Julii Corydoras (False Julii) is peaceful (0/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Dusky Millions Fish and Julii Corydoras (False Julii) need?

Both species overlap in the 7–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Will Dusky Millions Fish nip Julii Corydoras (False Julii)'s fins?

Dusky Millions Fish is a known fin nipper. If Julii Corydoras (False Julii) has long or flowing fins, there is a real risk of fin damage. Keeping Dusky Millions Fish in a larger group can help redirect nipping behaviour toward conspecifics.

Editorial Review

Guidarium Editorial Desk

Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.

Last reviewed
May 4, 2026
Last updated
May 4, 2026
Issues or corrections?
Contact the editorial team

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