Can Amazon Leaf Fish and Blue Back Blue Eye Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 2, 2026
Not Recommended

Amazon Leaf Fish and Blue Back Blue Eye are not recommended as tank mates due to incompatible water types and conflicting pH requirements and incompatible hardness ranges 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

Amazon Leaf Fish

Monocirrhus polyacanthus

Blue Back Blue Eye

Pseudomugil cyanodorsalis

🐠Family Group
Amazon Leaf Fish
Other
Blue Back Blue Eye
Rainbowfish
Temperament
Amazon Leaf Fish
Peaceful (2/10)
Blue Back Blue Eye
Peaceful (2/10)
Temperature
✓ Compatible
Amazon Leaf Fish
23–29°C
Blue Back Blue Eye
22–30°C
pH Range
✗ No overlap
Amazon Leaf Fish
5–6.8
Blue Back Blue Eye
7–8.5
Hardness (dGH)
✗ No overlap
Amazon Leaf Fish
0–8
Blue Back Blue Eye
10–30
Water Type
✗ No overlap
Amazon Leaf Fish
Freshwater Only
Blue Back Blue Eye
Brackish Required
Flow Preference
✓ Compatible
Amazon Leaf Fish
Low
Blue Back Blue Eye
Moderate
Min Tank Volume
Combined: 75 L
Amazon Leaf Fish
75 L
Blue Back Blue Eye
38 L
Swimming Level
Shared: 2 zones
Amazon Leaf Fish
MiddleTop
Blue Back Blue Eye
TopMiddle
🏷️Behavior Tags
Amazon Leaf Fish
Piscivore (Eats small/nano fish)Shrimp EaterFry PredatorShy / Slow Moving (Easily Stressed)Nocturnal
Blue Back Blue Eye
Nano / Bite-sized (Predation Risk)Jumper (Lid Required)Hyperactive / Fast SwimmerFry Predator
Stocking calculator

Can your tank handle Amazon Leaf Fish and Blue Back Blue Eye?

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
Blue Back Blue Eye
Test both in my tank

Behaviour & Temperament

Both Amazon Leaf Fish and Blue Back Blue Eye 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 Blue Back Blue Eye 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.

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: Hyperactive swimmers can stress shy, slow-moving species through constant motion. Shrimp eaters may also prey on very small nano fish.

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

Water Parameters

The safe temperature window for both species falls between 23°C and 29°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

The pH requirements of Amazon Leaf Fish (5–6.8) and Blue Back Blue Eye (7–8.5) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Amazon Leaf Fish needs 0–8 dGH while Blue Back Blue Eye requires 10–30 dGH.

Crucially, these species require different water types — one needs freshwater while the other requires brackish conditions. This is a hard barrier to keeping them together.

Tank Setup

To house Amazon Leaf Fish and Blue Back Blue Eye together, plan for an aquarium of at least 75 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: Leaf Litter/Blackwater, Plants - Densely covered, Driftwood (Digestion/Hiding), Plants - Floating, Sand (Sifters). 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

Amazon Leaf Fish and Blue Back Blue Eye 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 Amazon Leaf Fish and Blue Back Blue Eye.

Show 17 more tank sizes

Diet & Feeding

Feeding time deserves special attention with this pairing. Amazon Leaf Fish is a known shrimp eater and may prey on small invertebrates or nano fish like Blue Back Blue Eye.

Frequently Asked Questions

Can Amazon Leaf Fish and Blue Back Blue Eye live together?

No. This combination is not recommended. Key incompatibilities — such as different water type needs — make cohabitation unsafe.

What size tank do Amazon Leaf Fish and Blue Back Blue Eye need?

A minimum of 75 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 Amazon Leaf Fish and Blue Back Blue Eye together?

Keep the aquarium between 23°C and 29°C. A target of around 26.0°C sits comfortably within both species' preferred ranges.

Are Amazon Leaf Fish or Blue Back Blue Eye aggressive?

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

What pH do Amazon Leaf Fish and Blue Back Blue Eye need?

Their pH requirements do not overlap. Amazon Leaf Fish prefers 5–6.8, while Blue Back Blue Eye needs 7–8.5. This makes them incompatible in the same water chemistry.

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 2, 2026
Last updated
May 2, 2026
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