Can Flag Tetra and Orange Peacock Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 7, 2026
Not Recommended

Flag Tetra and Orange Peacock 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

Flag Tetra

Hyphessobrycon heterorhabdus

Orange Peacock

Aulonocara stuartgranti maleri

🐠Family Group
Flag Tetra
Characins
Orange Peacock
Cichlids - African
Temperament
Flag Tetra
Peaceful (1/10)
Orange Peacock
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Flag Tetra
22–28°C
Orange Peacock
24–28°C
pH Range
✗ No overlap
Flag Tetra
5.5–7.5
Orange Peacock
7.8–8.6
Hardness (dGH)
✓ Compatible
Flag Tetra
2–12
Orange Peacock
10–25
Water Type
✓ Compatible
Flag Tetra
Freshwater Only
Orange Peacock
Freshwater Only
Flow Preference
✓ Compatible
Flag Tetra
Moderate
Orange Peacock
Moderate
Min Tank Volume
Combined: 208 L
Flag Tetra
55 L
Orange Peacock
208 L
Swimming Level
Shared: 1 zone
Flag Tetra
Middle
Orange Peacock
BottomMiddle
🏷️Behavior Tags
Flag Tetra
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerFry Predator
Orange Peacock
Digger (Disturbs Substrate)
Stocking calculator

Can your tank handle Flag Tetra and Orange Peacock?

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.

Flag Tetra
Orange Peacock
Test both in my tank

Behaviour & Temperament

Flag Tetra is a peaceful species (1/10), while Orange Peacock is moderately assertive (6/10). This notable difference means Orange Peacock may occasionally assert dominance over Flag Tetra.

Flag Tetra and Orange Peacock both frequent the 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.

Water Parameters

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

The pH requirements of Flag Tetra (5.5–7.5) and Orange Peacock (7.8–8.6) 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 Flag Tetra and Orange Peacock together, plan for an aquarium of at least 208 litres with a minimum length of 120 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, Leaf Litter/Blackwater, 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

Flag Tetra and Orange Peacock 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 Flag Tetra and Orange Peacock.

Show 5 more tank sizes

Frequently Asked Questions

Can Flag Tetra and Orange Peacock live together?

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

What size tank do Flag Tetra and Orange Peacock need?

A minimum of 208 litres (tank length at least 120 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 Flag Tetra and Orange Peacock together?

Keep the aquarium between 24°C and 28°C. A target of around 26.0°C sits comfortably within both species' preferred ranges.

Are Flag Tetra or Orange Peacock aggressive?

Flag Tetra is peaceful (1/10) and Orange Peacock 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 Flag Tetra and Orange Peacock need?

Their pH requirements do not overlap. Flag Tetra prefers 5.5–7.5, while Orange Peacock needs 7.8–8.6. This makes them incompatible in the same water chemistry.

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

Related Comparisons