Can Amazon Leaf Fish and Cairns Rainbowfish Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 3, 2026
Possible with Caution

Keeping Amazon Leaf Fish and Cairns Rainbowfish together is possible but requires caution due to potential behavioral clashes and mismatched flow preferences. Provide a spacious tank of at least 110 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Amazon Leaf Fish

Monocirrhus polyacanthus

Cairns Rainbowfish

Cairnsichthys rhombosomoides

🐠Family Group
Amazon Leaf Fish
Other
Cairns Rainbowfish
Rainbowfish
Temperament
Amazon Leaf Fish
Peaceful (2/10)
Cairns Rainbowfish
Peaceful (2/10)
Temperature
✓ Compatible
Amazon Leaf Fish
23–29°C
Cairns Rainbowfish
20–26°C
pH Range
✓ Compatible
Amazon Leaf Fish
5–6.8
Cairns Rainbowfish
6.5–7.6
Hardness (dGH)
✓ Compatible
Amazon Leaf Fish
0–8
Cairns Rainbowfish
2–10
Water Type
✓ Compatible
Amazon Leaf Fish
Freshwater Only
Cairns Rainbowfish
Freshwater Only
Flow Preference
✗ No overlap
Amazon Leaf Fish
Low
Cairns Rainbowfish
High
Min Tank Volume
Combined: 110 L
Amazon Leaf Fish
75 L
Cairns Rainbowfish
110 L
Swimming Level
Shared: 2 zones
Amazon Leaf Fish
MiddleTop
Cairns Rainbowfish
MiddleTop
🏷️Behavior Tags
Amazon Leaf Fish
Piscivore (Eats small/nano fish)Shrimp EaterFry PredatorShy / Slow Moving (Easily Stressed)Nocturnal
Cairns Rainbowfish
Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
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Can your tank handle Amazon Leaf Fish and Cairns Rainbowfish?

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.

Amazon Leaf Fish
Cairns Rainbowfish
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Behaviour & Temperament

Both Amazon Leaf Fish and Cairns Rainbowfish are peaceful species with an aggression score of 2/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Amazon Leaf Fish and Cairns Rainbowfish 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.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Amazon Leaf Fish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Cairns Rainbowfish is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat.

Water Parameters

The safe temperature window for both species falls between 23°C and 26°C. Aim for the midpoint of this range (around 24.5°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 and 6.8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 2–8 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Amazon Leaf Fish and Cairns Rainbowfish together, plan for an aquarium of at least 110 litres with a minimum length of 90 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: Leaf Litter/Blackwater, Plants - Densely covered, Driftwood (Digestion/Hiding), Plants - Floating, Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Amazon Leaf Fish prefers Low (Still Water) flow while Cairns Rainbowfish 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. Amazon Leaf Fish and Cairns Rainbowfish 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 Amazon Leaf Fish and Cairns Rainbowfish.

Show 10 more tank sizes

Frequently Asked Questions

Can Amazon Leaf Fish and Cairns Rainbowfish live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 110 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Amazon Leaf Fish and Cairns Rainbowfish need?

A minimum of 110 litres (tank length at least 90 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 Amazon Leaf Fish and Cairns Rainbowfish together?

Keep the aquarium between 23°C and 26°C. A target of around 24.5°C sits comfortably within both species' preferred ranges.

Are Amazon Leaf Fish or Cairns Rainbowfish aggressive?

Amazon Leaf Fish is peaceful (2/10) and Cairns Rainbowfish is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Amazon Leaf Fish and Cairns Rainbowfish need?

Both species overlap in the 6.5–6.8 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Does Amazon Leaf Fish being nocturnal affect compatibility?

Amazon Leaf Fish 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 Amazon Leaf Fish during evening hours.

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
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