Can Delhezi Bichir (Armored Bichir) and Mountain Rainbowfish Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 6, 2026
Possible with Caution

Keeping Delhezi Bichir (Armored Bichir) and Mountain Rainbowfish together is possible but requires caution due to differing aggression levels and mismatched flow preferences. Provide a spacious tank of at least 280 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Delhezi Bichir (Armored Bichir)

Polypterus delhezi

Mountain Rainbowfish

Melanotaenia monticola

🐠Family Group
Delhezi Bichir (Armored Bichir)
Oddballs
Mountain Rainbowfish
Rainbowfish
Temperament
Delhezi Bichir (Armored Bichir)
Semi-Aggressive (6/10)
Mountain Rainbowfish
Peaceful (2/10)
Temperature
✓ Compatible
Delhezi Bichir (Armored Bichir)
24–30°C
Mountain Rainbowfish
17–24°C
pH Range
✓ Compatible
Delhezi Bichir (Armored Bichir)
6–8
Mountain Rainbowfish
7.4–8.5
Hardness (dGH)
✓ Compatible
Delhezi Bichir (Armored Bichir)
5–20
Mountain Rainbowfish
8–20
Water Type
✓ Compatible
Delhezi Bichir (Armored Bichir)
Freshwater Only
Mountain Rainbowfish
Freshwater Only
Flow Preference
✗ No overlap
Delhezi Bichir (Armored Bichir)
Low
Mountain Rainbowfish
High
Min Tank Volume
Combined: 280 L
Delhezi Bichir (Armored Bichir)
280 L
Mountain Rainbowfish
110 L
Swimming Level
✓ Different zones
Delhezi Bichir (Armored Bichir)
Bottom
Mountain Rainbowfish
TopMiddle
🏷️Behavior Tags
Delhezi Bichir (Armored Bichir)
Piscivore (Eats small/nano fish)Shrimp EaterJumper (Lid Required)Nocturnal
Mountain Rainbowfish
Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Stocking calculator

Can your tank handle Delhezi Bichir (Armored Bichir) and Mountain Rainbowfish?

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)
Mountain Rainbowfish
Test both in my tank

Behaviour & Temperament

Delhezi Bichir (Armored Bichir) is a moderately assertive species (6/10), while Mountain Rainbowfish is peaceful (2/10). This notable difference means Delhezi Bichir (Armored Bichir) may occasionally assert dominance over Mountain Rainbowfish.

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

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.

To improve the chances of a peaceful coexistence in this community tank: A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat.

Water Parameters

The safe temperature window for both species falls between 24°C and 24°C. Aim for the midpoint of this range (around 24.0°C) for optimal comfort.

Both fish can tolerate a pH between 7.4 and 8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 8–20 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Delhezi Bichir (Armored Bichir) and Mountain Rainbowfish 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.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.

Delhezi Bichir (Armored Bichir) prefers Low (Still Water) flow while Mountain Rainbowfish needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

Why This Pairing Needs Extra Planning in Practice

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Delhezi Bichir (Armored Bichir) and Mountain Rainbowfish need extra room, more cover, and closer observation during the first few weeks so small aggression, feeding, or territory issues do not snowball into a long-term problem.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Delhezi Bichir (Armored Bichir) and Mountain Rainbowfish.

Show 1 more tank size

Frequently Asked Questions

Can Delhezi Bichir (Armored Bichir) and Mountain Rainbowfish live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 280 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Delhezi Bichir (Armored Bichir) and Mountain Rainbowfish 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 Mountain Rainbowfish together?

Keep the aquarium between 24°C and 24°C. A target of around 24.0°C sits comfortably within both species' preferred ranges.

Are Delhezi Bichir (Armored Bichir) or Mountain Rainbowfish aggressive?

Delhezi Bichir (Armored Bichir) is moderately assertive (6/10) and Mountain Rainbowfish is peaceful (2/10). 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 Mountain Rainbowfish need?

Both species overlap in the 7.4–8 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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