Can Brilliant Rasbora and Neolamprologus Similis Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 6, 2026
Not Recommended

Brilliant Rasbora and Neolamprologus Similis are not recommended as tank mates due to conflicting pH requirements. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Brilliant Rasbora

Rasbora einthovenii

Neolamprologus Similis

Neolamprologus similis

🐠Family Group
Brilliant Rasbora
Cyprinids
Neolamprologus Similis
Cichlids - African
Temperament
Brilliant Rasbora
Peaceful (1/10)
Neolamprologus Similis
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Brilliant Rasbora
22–26°C
Neolamprologus Similis
24–27°C
pH Range
✗ No overlap
Brilliant Rasbora
5.5–7.5
Neolamprologus Similis
7.8–9
Hardness (dGH)
✓ Compatible
Brilliant Rasbora
2–10
Neolamprologus Similis
10–25
Water Type
✓ Compatible
Brilliant Rasbora
Freshwater Only
Neolamprologus Similis
Freshwater Only
Flow Preference
✓ Compatible
Brilliant Rasbora
Low
Neolamprologus Similis
Moderate
Min Tank Volume
Combined: 60 L
Brilliant Rasbora
60 L
Neolamprologus Similis
38 L
Swimming Level
✓ Different zones
Brilliant Rasbora
TopMiddle
Neolamprologus Similis
Bottom
🏷️Behavior Tags
Brilliant Rasbora
Hyperactive / Fast SwimmerJumper (Lid Required)Shy / Slow Moving (Easily Stressed)
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 Brilliant Rasbora 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.

Brilliant Rasbora
Neolamprologus Similis
Test both in my tank

Behaviour & Temperament

Brilliant Rasbora is a peaceful species (1/10), while Neolamprologus Similis is moderately assertive (6/10). This notable difference means Neolamprologus Similis may occasionally assert dominance over Brilliant Rasbora.

In terms of spatial distribution, Brilliant Rasbora prefers the Top (Surface) and Middle (Open Water) zones, whereas Neolamprologus Similis 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: Brilliant Rasbora 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 26°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

The pH requirements of Brilliant Rasbora (5.5–7.5) 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 10–10 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Brilliant Rasbora and Neolamprologus Similis together, plan for an aquarium of at least 60 litres with a minimum length of 60 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: Plants - Densely covered, Plants - Floating, Leaf Litter/Blackwater, 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

Brilliant Rasbora 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 Brilliant Rasbora and Neolamprologus Similis.

Show 19 more tank sizes

Frequently Asked Questions

Can Brilliant Rasbora 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 Brilliant Rasbora and Neolamprologus Similis need?

A minimum of 60 litres (tank length at least 60 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 Brilliant Rasbora and Neolamprologus Similis together?

Keep the aquarium between 24°C and 26°C. A target of around 25.0°C sits comfortably within both species' preferred ranges.

Are Brilliant Rasbora or Neolamprologus Similis aggressive?

Brilliant Rasbora is peaceful (1/10) and Neolamprologus Similis is moderately assertive (6/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Brilliant Rasbora and Neolamprologus Similis need?

Their pH requirements do not overlap. Brilliant Rasbora prefers 5.5–7.5, 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.

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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