Can Cairns Rainbowfish and Trout Cichlid (Champsochromis) Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 3, 2026
Not Recommended

Cairns Rainbowfish and Trout Cichlid (Champsochromis) 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

Cairns Rainbowfish

Cairnsichthys rhombosomoides

Trout Cichlid (Champsochromis)

Champsochromis caeruleus

🐠Family Group
Cairns Rainbowfish
Rainbowfish
Trout Cichlid (Champsochromis)
Cichlids - African
Temperament
Cairns Rainbowfish
Peaceful (2/10)
Trout Cichlid (Champsochromis)
Aggressive (7/10)
Temperature
✓ Compatible
Cairns Rainbowfish
20–26°C
Trout Cichlid (Champsochromis)
24–28°C
pH Range
✗ No overlap
Cairns Rainbowfish
6.5–7.6
Trout Cichlid (Champsochromis)
7.8–8.6
Hardness (dGH)
✓ Compatible
Cairns Rainbowfish
2–10
Trout Cichlid (Champsochromis)
10–25
Water Type
✓ Compatible
Cairns Rainbowfish
Freshwater Only
Trout Cichlid (Champsochromis)
Freshwater Only
Flow Preference
✓ Compatible
Cairns Rainbowfish
High
Trout Cichlid (Champsochromis)
Moderate
Min Tank Volume
Combined: 500 L
Cairns Rainbowfish
110 L
Trout Cichlid (Champsochromis)
500 L
Swimming Level
Shared: 2 zones
Cairns Rainbowfish
MiddleTop
Trout Cichlid (Champsochromis)
TopMiddle
🏷️Behavior Tags
Cairns Rainbowfish
Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Trout Cichlid (Champsochromis)
Piscivore (Eats small/nano fish)Hyperactive / Fast SwimmerJumper (Lid Required)Territorial (Defends specific area)Aggressive to same species/look-alikes
Stocking calculator

Can your tank handle Cairns Rainbowfish and Trout Cichlid (Champsochromis)?

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.

Cairns Rainbowfish
Trout Cichlid (Champsochromis)
Test both in my tank

Behaviour & Temperament

Cairns Rainbowfish is a peaceful species (2/10), while Trout Cichlid (Champsochromis) is semi-aggressive (7/10). This notable difference means Trout Cichlid (Champsochromis) may occasionally assert dominance over Cairns Rainbowfish.

Cairns Rainbowfish and Trout Cichlid (Champsochromis) both frequent the Middle (Open Water) and Top (Surface) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

Worth noting: Cairns Rainbowfish 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 Cairns Rainbowfish (6.5–7.6) and Trout Cichlid (Champsochromis) (7.8–8.6) 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 Cairns Rainbowfish and Trout Cichlid (Champsochromis) together, plan for an aquarium of at least 500 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.

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: Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding), Leaf Litter/Blackwater, Sand (Sifters). Meeting these requirements will help both species thrive.

Both species do well with high (river/stream) water movement, so a standard filtration setup rated for the tank volume should suffice.

Why This Pairing Usually Fails in Practice

Cairns Rainbowfish and Trout Cichlid (Champsochromis) 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 Cairns Rainbowfish and Trout Cichlid (Champsochromis).

Frequently Asked Questions

Can Cairns Rainbowfish and Trout Cichlid (Champsochromis) live together?

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

What size tank do Cairns Rainbowfish and Trout Cichlid (Champsochromis) need?

A minimum of 500 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 Cairns Rainbowfish and Trout Cichlid (Champsochromis) 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 Cairns Rainbowfish or Trout Cichlid (Champsochromis) aggressive?

Cairns Rainbowfish is peaceful (2/10) and Trout Cichlid (Champsochromis) is semi-aggressive (7/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Cairns Rainbowfish and Trout Cichlid (Champsochromis) need?

Their pH requirements do not overlap. Cairns Rainbowfish prefers 6.5–7.6, while Trout Cichlid (Champsochromis) needs 7.8–8.6. This makes them incompatible in the same water chemistry.

How do I manage Trout Cichlid (Champsochromis)'s territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Trout Cichlid (Champsochromis) 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 3, 2026
Last updated
May 3, 2026
Issues or corrections?
Contact the editorial team

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