Can Betta Smaragdina and Weeksi Bichir Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 11, 2026
Possible with Caution

Keeping Betta Smaragdina and Weeksi Bichir together is possible but requires caution, though some care is needed. Provide a spacious tank of at least 470 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Betta Smaragdina

Betta smaragdina

Weeksi Bichir

Polypterus weeksii

🐠Family Group
Betta Smaragdina
Anabantoids
Weeksi Bichir
Oddballs
Temperament
Betta Smaragdina
Semi-Aggressive (5/10)
Weeksi Bichir
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Betta Smaragdina
22–28°C
Weeksi Bichir
24–28°C
pH Range
✓ Compatible
Betta Smaragdina
5.5–7.5
Weeksi Bichir
6–7.5
Hardness (dGH)
✓ Compatible
Betta Smaragdina
2–12
Weeksi Bichir
5–15
Water Type
✓ Compatible
Betta Smaragdina
Freshwater Only
Weeksi Bichir
Freshwater Only
Flow Preference
✓ Compatible
Betta Smaragdina
Low
Weeksi Bichir
Low
Min Tank Volume
Combined: 470 L
Betta Smaragdina
20 L
Weeksi Bichir
470 L
Swimming Level
✓ Different zones
Betta Smaragdina
TopMiddle
Weeksi Bichir
Bottom
🏷️Behavior Tags
Betta Smaragdina
Shrimp EaterFry PredatorJumper (Lid Required)Territorial (Defends specific area)Aggressive to same species/look-alikes
Weeksi Bichir
Piscivore (Eats small/nano fish)NocturnalJumper (Lid Required)Shrimp EaterFry Predator
Stocking calculator

Can your tank handle Betta Smaragdina and Weeksi Bichir?

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.

Betta Smaragdina
Weeksi Bichir
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Behaviour & Temperament

Betta Smaragdina is a moderately assertive species (5/10), while Weeksi Bichir is moderately assertive (6/10). This modest difference means Weeksi Bichir may occasionally assert dominance over Betta Smaragdina.

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

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

To improve the chances of a peaceful coexistence in this community tank: Provide a significantly larger tank (at least 50% more volume than the minimum) to allow both Betta Smaragdina and Weeksi Bichir to establish separate territories. Add plenty of line-of-sight breaks using driftwood, rocks, and dense planting to reduce territorial confrontations.

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 Betta Smaragdina and Weeksi Bichir together, plan for an aquarium of at least 470 litres with a minimum length of 150 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: Plants - Densely covered, Plants - Floating, Leaf Litter/Blackwater, 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 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. Betta Smaragdina and Weeksi Bichir 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 Betta Smaragdina and Weeksi Bichir.

Frequently Asked Questions

Can Betta Smaragdina and Weeksi Bichir live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 470 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Betta Smaragdina and Weeksi Bichir need?

A minimum of 470 litres (tank length at least 150 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 Betta Smaragdina and Weeksi Bichir 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 Betta Smaragdina or Weeksi Bichir aggressive?

Betta Smaragdina is moderately assertive (5/10) and Weeksi Bichir is moderately assertive (6/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Betta Smaragdina and Weeksi Bichir 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.

How do I manage Betta Smaragdina's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Betta Smaragdina 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.

Does Weeksi Bichir being nocturnal affect compatibility?

Weeksi 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 Weeksi Bichir during evening hours.

Editorial Review

Guidarium Editorial Desk

Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.

Last reviewed
May 11, 2026
Last updated
May 11, 2026
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