Can Dusky Millions Fish and Peacock Bass Orinocensis Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 7, 2026
Not Recommended

Dusky Millions Fish and Peacock Bass Orinocensis are not recommended as tank mates due to no temperature overlap. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Dusky Millions Fish

Phalloceros caudimaculatus

Peacock Bass Orinocensis

Cichla orinocensis

🐠Family Group
Dusky Millions Fish
Livebearers
Peacock Bass Orinocensis
Cichlids - South American
Temperament
Dusky Millions Fish
Peaceful (2/10)
Peacock Bass Orinocensis
Aggressive (8/10)
Temperature
✗ No overlap
Dusky Millions Fish
16–24°C
Peacock Bass Orinocensis
26–31°C
pH Range
✓ Compatible
Dusky Millions Fish
7–8
Peacock Bass Orinocensis
5.5–7.5
Hardness (dGH)
✓ Compatible
Dusky Millions Fish
8–20
Peacock Bass Orinocensis
2–15
Water Type
✓ Compatible
Dusky Millions Fish
Brackish Tolerant
Peacock Bass Orinocensis
Freshwater Only
Flow Preference
✓ Compatible
Dusky Millions Fish
Low
Peacock Bass Orinocensis
Moderate
Min Tank Volume
Combined: 750 L
Dusky Millions Fish
40 L
Peacock Bass Orinocensis
750 L
Swimming Level
Shared: 2 zones
Dusky Millions Fish
TopMiddle
Peacock Bass Orinocensis
MiddleTop
🏷️Behavior Tags
Dusky Millions Fish
Hyperactive / Fast SwimmerPlant DestroyerFin Nipper
Peacock Bass Orinocensis
Piscivore (Eats small/nano fish)Generally AggressiveTerritorial (Defends specific area)Jumper (Lid Required)Hyperactive / Fast SwimmerDigger (Disturbs Substrate)
Stocking calculator

Can your tank handle Dusky Millions Fish and Peacock Bass Orinocensis?

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
Peacock Bass Orinocensis
Test both in my tank

Behaviour & Temperament

Dusky Millions Fish is a peaceful species (2/10), while Peacock Bass Orinocensis is semi-aggressive (8/10). This notable difference means Peacock Bass Orinocensis may occasionally assert dominance over Dusky Millions Fish.

Large aggression gap (6 points) between Dusky Millions Fish and Peacock Bass Orinocensis increases stress risk for the more peaceful fish.

Dusky Millions Fish and Peacock Bass Orinocensis both frequent the Top (Surface) 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.

Worth noting: Peacock Bass Orinocensis is a known jumper, so a tight-fitting lid is essential.

Water Parameters

There is no temperature overlap between Dusky Millions Fish (16–24°C) and Peacock Bass Orinocensis (26–31°C). This fundamental mismatch makes long-term cohabitation impractical.

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 Peacock Bass Orinocensis together, plan for an aquarium of at least 750 litres with a minimum length of 200 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), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding). 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 Usually Fails in Practice

Dusky Millions Fish and Peacock Bass Orinocensis 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 Dusky Millions Fish and Peacock Bass Orinocensis live together?

No. This combination is not recommended. Key incompatibilities — such as non-overlapping temperature ranges — make cohabitation unsafe.

What size tank do Dusky Millions Fish and Peacock Bass Orinocensis need?

A minimum of 750 litres (tank length at least 200 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 Peacock Bass Orinocensis together?

Unfortunately, there is no temperature range that satisfies both species. Dusky Millions Fish requires 16–24°C, while Peacock Bass Orinocensis needs 26–31°C.

Are Dusky Millions Fish or Peacock Bass Orinocensis aggressive?

Dusky Millions Fish is peaceful (2/10) and Peacock Bass Orinocensis is semi-aggressive (8/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Dusky Millions Fish and Peacock Bass Orinocensis 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 Peacock Bass Orinocensis's fins?

Dusky Millions Fish is a known fin nipper. If Peacock Bass Orinocensis 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.

How do I manage Peacock Bass Orinocensis's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Peacock Bass Orinocensis 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 7, 2026
Last updated
May 7, 2026
Issues or corrections?
Contact the editorial team

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