Can Delhezi Bichir (Armored Bichir) and Flag Tetra Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 6, 2026
Not Recommended

Delhezi Bichir (Armored Bichir) and Flag Tetra are not recommended as tank mates due to piscivorous fish will prey on nano-sized tank mates.. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Delhezi Bichir (Armored Bichir)

Polypterus delhezi

Flag Tetra

Hyphessobrycon heterorhabdus

🐠Family Group
Delhezi Bichir (Armored Bichir)
Oddballs
Flag Tetra
Characins
Temperament
Delhezi Bichir (Armored Bichir)
Semi-Aggressive (6/10)
Flag Tetra
Peaceful (1/10)
Temperature
✓ Compatible
Delhezi Bichir (Armored Bichir)
24–30°C
Flag Tetra
22–28°C
pH Range
✓ Compatible
Delhezi Bichir (Armored Bichir)
6–8
Flag Tetra
5.5–7.5
Hardness (dGH)
✓ Compatible
Delhezi Bichir (Armored Bichir)
5–20
Flag Tetra
2–12
Water Type
✓ Compatible
Delhezi Bichir (Armored Bichir)
Freshwater Only
Flag Tetra
Freshwater Only
Flow Preference
✓ Compatible
Delhezi Bichir (Armored Bichir)
Low
Flag Tetra
Moderate
Min Tank Volume
Combined: 280 L
Delhezi Bichir (Armored Bichir)
280 L
Flag Tetra
55 L
Swimming Level
✓ Different zones
Delhezi Bichir (Armored Bichir)
Bottom
Flag Tetra
Middle
🏷️Behavior Tags
Delhezi Bichir (Armored Bichir)
Piscivore (Eats small/nano fish)Shrimp EaterJumper (Lid Required)Nocturnal
Flag Tetra
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerFry Predator
Stocking calculator

Can your tank handle Delhezi Bichir (Armored Bichir) and Flag Tetra?

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.

Delhezi Bichir (Armored Bichir)
Flag Tetra
Test both in my tank

Behaviour & Temperament

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

In terms of spatial distribution, Delhezi Bichir (Armored Bichir) prefers the Bottom (Substrate) zone, whereas Flag Tetra occupies the Middle (Open Water) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

There is a critical concern: the Piscivore (Eats small/nano fish) behaviour of one fish directly conflicts with the Nano / Bite-sized (Predation Risk) trait of the other — piscivorous fish will prey on nano-sized tank mates..

Additional behavioural considerations to keep in mind: Shrimp eaters may also prey on very small nano fish.

Worth noting: Delhezi Bichir (Armored Bichir) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Delhezi Bichir (Armored Bichir) is a known jumper, so a tight-fitting lid is essential.

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.

Both fish can tolerate a pH between 6 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 5–12 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Delhezi Bichir (Armored Bichir) and Flag Tetra together, plan for an aquarium of at least 280 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: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding), Plants - Densely covered, Leaf Litter/Blackwater. 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

Delhezi Bichir (Armored Bichir) and Flag Tetra 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 Delhezi Bichir (Armored Bichir) and Flag Tetra.

Show 1 more tank size

Diet & Feeding

Feeding time deserves special attention with this pairing. Delhezi Bichir (Armored Bichir) is a known shrimp eater and may prey on small invertebrates or nano fish like Flag Tetra.

Frequently Asked Questions

Can Delhezi Bichir (Armored Bichir) and Flag Tetra live together?

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

What size tank do Delhezi Bichir (Armored Bichir) and Flag Tetra need?

A minimum of 280 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 Delhezi Bichir (Armored Bichir) and Flag Tetra 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 Delhezi Bichir (Armored Bichir) or Flag Tetra aggressive?

Delhezi Bichir (Armored Bichir) is moderately assertive (6/10) and Flag Tetra is peaceful (1/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Delhezi Bichir (Armored Bichir) and Flag Tetra need?

Both species overlap in the 6–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Does Delhezi Bichir (Armored Bichir) being nocturnal affect compatibility?

Delhezi Bichir (Armored Bichir) 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 Delhezi Bichir (Armored Bichir) during evening hours.

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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