Can African Knifefish and Neolamprologus Similis Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 6, 2026
Not Recommended

African Knifefish and Neolamprologus Similis are not recommended as tank mates due to conflicting pH requirements and 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

African Knifefish

Xenomystus nigri

Neolamprologus Similis

Neolamprologus similis

🐠Family Group
African Knifefish
Oddballs
Neolamprologus Similis
Cichlids - African
Temperament
African Knifefish
Semi-Aggressive (5/10)
Neolamprologus Similis
Semi-Aggressive (6/10)
Temperature
✓ Compatible
African Knifefish
23–28°C
Neolamprologus Similis
24–27°C
pH Range
✗ No overlap
African Knifefish
6–7.5
Neolamprologus Similis
7.8–9
Hardness (dGH)
✓ Compatible
African Knifefish
2–15
Neolamprologus Similis
10–25
Water Type
✓ Compatible
African Knifefish
Freshwater Only
Neolamprologus Similis
Freshwater Only
Flow Preference
✓ Compatible
African Knifefish
Low
Neolamprologus Similis
Moderate
Min Tank Volume
Combined: 200 L
African Knifefish
200 L
Neolamprologus Similis
38 L
Swimming Level
Shared: 1 zone
African Knifefish
MiddleBottom
Neolamprologus Similis
Bottom
🏷️Behavior Tags
African Knifefish
Piscivore (Eats small/nano fish)Shrimp EaterNocturnalShy / Slow Moving (Easily Stressed)Aggressive to same species/look-alikes
Neolamprologus Similis
Nano / Bite-sized (Predation Risk)Territorial (Defends specific area)Digger (Disturbs Substrate)Aggressive to same species/look-alikes
Stocking calculator

Can your tank handle African Knifefish and Neolamprologus Similis?

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.

African Knifefish
Neolamprologus Similis
Test both in my tank

Behaviour & Temperament

African Knifefish is a moderately assertive species (5/10), while Neolamprologus Similis is moderately assertive (6/10). This modest difference means Neolamprologus Similis may occasionally assert dominance over African Knifefish.

African Knifefish and Neolamprologus Similis both frequent the Bottom (Substrate) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

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: African Knifefish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters.

Water Parameters

The safe temperature window for both species falls between 24°C and 27°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

The pH requirements of African Knifefish (6–7.5) and Neolamprologus Similis (7.8–9) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 10–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house African Knifefish and Neolamprologus Similis 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.

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: Driftwood (Digestion/Hiding), Smooth Gravel (Sensitive Barbels), Plants - Floating, Sand (Sifters), Shells (Breeding/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 Usually Fails in Practice

African Knifefish and Neolamprologus Similis 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 African Knifefish and Neolamprologus Similis.

Show 5 more tank sizes

Diet & Feeding

Feeding time deserves special attention with this pairing. African Knifefish is a known shrimp eater and may prey on small invertebrates or nano fish like Neolamprologus Similis.

Frequently Asked Questions

Can African Knifefish and Neolamprologus Similis live together?

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

What size tank do African Knifefish and Neolamprologus Similis 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 African Knifefish and Neolamprologus Similis together?

Keep the aquarium between 24°C and 27°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are African Knifefish or Neolamprologus Similis aggressive?

African Knifefish is moderately assertive (5/10) and Neolamprologus Similis is moderately assertive (6/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do African Knifefish and Neolamprologus Similis need?

Their pH requirements do not overlap. African Knifefish prefers 6–7.5, while Neolamprologus Similis needs 7.8–9. This makes them incompatible in the same water chemistry.

How do I manage Neolamprologus Similis's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Neolamprologus Similis 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 African Knifefish being nocturnal affect compatibility?

African Knifefish 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 African Knifefish 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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