Can Buettikoferi Bichir and Northern Mountain Swordtail Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 7, 2026
Possible with Caution

Keeping Buettikoferi Bichir and Northern Mountain Swordtail together is possible but requires caution due to mismatched flow preferences. Provide a spacious tank of at least 200 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Buettikoferi Bichir

Polypterus palmas buettikoferi

Northern Mountain Swordtail

Xiphophorus nezahualcoyotl

🐠Family Group
Buettikoferi Bichir
Oddballs
Northern Mountain Swordtail
Livebearers
Temperament
Buettikoferi Bichir
Semi-Aggressive (6/10)
Northern Mountain Swordtail
Mostly Peaceful (3/10)
Temperature
✓ Compatible
Buettikoferi Bichir
24–28°C
Northern Mountain Swordtail
20–25°C
pH Range
✓ Compatible
Buettikoferi Bichir
6.5–7.5
Northern Mountain Swordtail
7–8
Hardness (dGH)
✓ Compatible
Buettikoferi Bichir
5–15
Northern Mountain Swordtail
8–20
Water Type
✓ Compatible
Buettikoferi Bichir
Freshwater Only
Northern Mountain Swordtail
Freshwater Only
Flow Preference
✗ No overlap
Buettikoferi Bichir
Low
Northern Mountain Swordtail
High
Min Tank Volume
Combined: 200 L
Buettikoferi Bichir
200 L
Northern Mountain Swordtail
110 L
Swimming Level
✓ Different zones
Buettikoferi Bichir
Bottom
Northern Mountain Swordtail
TopMiddle
🏷️Behavior Tags
Buettikoferi Bichir
Piscivore (Eats small/nano fish)Shrimp EaterFry PredatorJumper (Lid Required)Nocturnal
Northern Mountain Swordtail
Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Stocking calculator

Can your tank handle Buettikoferi Bichir and Northern Mountain Swordtail?

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.

Buettikoferi Bichir
Northern Mountain Swordtail
Test both in my tank

Behaviour & Temperament

Buettikoferi Bichir is a moderately assertive species (6/10), while Northern Mountain Swordtail is generally mild-mannered (3/10). This modest difference means Buettikoferi Bichir may occasionally assert dominance over Northern Mountain Swordtail.

In terms of spatial distribution, Buettikoferi Bichir prefers the Bottom (Substrate) zone, whereas Northern Mountain Swordtail 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: Buettikoferi Bichir is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Buettikoferi 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 25°C. Aim for the midpoint of this range (around 24.5°C) for optimal comfort.

Both fish can tolerate a pH between 7 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 Buettikoferi Bichir and Northern Mountain Swordtail together, plan for an aquarium of at least 200 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), Plants - Densely covered. Meeting these requirements will help both species thrive.

Buettikoferi Bichir prefers Low (Still Water) flow while Northern Mountain Swordtail 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. Buettikoferi Bichir and Northern Mountain Swordtail 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 Buettikoferi Bichir and Northern Mountain Swordtail.

Show 5 more tank sizes

Frequently Asked Questions

Can Buettikoferi Bichir and Northern Mountain Swordtail live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 200 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Buettikoferi Bichir and Northern Mountain Swordtail need?

A minimum of 200 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 Buettikoferi Bichir and Northern Mountain Swordtail together?

Keep the aquarium between 24°C and 25°C. A target of around 24.5°C sits comfortably within both species' preferred ranges.

Are Buettikoferi Bichir or Northern Mountain Swordtail aggressive?

Buettikoferi Bichir is moderately assertive (6/10) and Northern Mountain Swordtail is generally mild-mannered (3/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Buettikoferi Bichir and Northern Mountain Swordtail need?

Both species overlap in the 7–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Does Buettikoferi Bichir being nocturnal affect compatibility?

Buettikoferi 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 Buettikoferi Bichir during evening hours.

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

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