Can Guinean Bichir and Mountain Rainbowfish Live Together?

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

Keeping Guinean Bichir and Mountain Rainbowfish together is possible but requires caution due to mismatched flow preferences. Provide a spacious tank of at least 680 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Guinean Bichir

Polypterus ansorgii

Mountain Rainbowfish

Melanotaenia monticola

🐠Family Group
Guinean Bichir
Oddballs
Mountain Rainbowfish
Rainbowfish
Temperament
Guinean Bichir
Semi-Aggressive (5/10)
Mountain Rainbowfish
Peaceful (2/10)
Temperature
✓ Compatible
Guinean Bichir
24–28°C
Mountain Rainbowfish
17–24°C
pH Range
✓ Compatible
Guinean Bichir
6.5–7.5
Mountain Rainbowfish
7.4–8.5
Hardness (dGH)
✓ Compatible
Guinean Bichir
5–15
Mountain Rainbowfish
8–20
Water Type
✓ Compatible
Guinean Bichir
Freshwater Only
Mountain Rainbowfish
Freshwater Only
Flow Preference
✗ No overlap
Guinean Bichir
Low
Mountain Rainbowfish
High
Min Tank Volume
Combined: 680 L
Guinean Bichir
680 L
Mountain Rainbowfish
110 L
Swimming Level
✓ Different zones
Guinean Bichir
Bottom
Mountain Rainbowfish
TopMiddle
🏷️Behavior Tags
Guinean Bichir
Piscivore (Eats small/nano fish)Jumper (Lid Required)Nocturnal
Mountain Rainbowfish
Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Stocking calculator

Can your tank handle Guinean 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.

Guinean Bichir
Mountain Rainbowfish
Test both in my tank

Behaviour & Temperament

Guinean Bichir is a moderately assertive species (5/10), while Mountain Rainbowfish is peaceful (2/10). This modest difference means Guinean Bichir may occasionally assert dominance over Mountain Rainbowfish.

In terms of spatial distribution, Guinean 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: Guinean Bichir is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Guinean 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 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 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 Guinean Bichir and Mountain Rainbowfish together, plan for an aquarium of at least 680 litres with a minimum length of 180 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), Plants - Floating. Meeting these requirements will help both species thrive.

Guinean 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. Guinean 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 Guinean Bichir and Mountain Rainbowfish.

Frequently Asked Questions

Can Guinean Bichir and Mountain Rainbowfish live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 680 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Guinean Bichir and Mountain Rainbowfish need?

A minimum of 680 litres (tank length at least 180 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 Guinean 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 Guinean Bichir or Mountain Rainbowfish aggressive?

Guinean Bichir is moderately assertive (5/10) and Mountain Rainbowfish is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Guinean Bichir and Mountain Rainbowfish need?

Both species overlap in the 7.4–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Does Guinean Bichir being nocturnal affect compatibility?

Guinean 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 Guinean 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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