Can Honey Blue Eye and Mountain Rainbowfish Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 6, 2026
Not Recommended

Honey Blue Eye and Mountain Rainbowfish 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

Honey Blue Eye

Pseudomugil mellis

Mountain Rainbowfish

Melanotaenia monticola

🐟Family Group
Honey Blue Eye
Rainbowfish
Mountain Rainbowfish
Rainbowfish
Temperament
Honey Blue Eye
Peaceful (2/10)
Mountain Rainbowfish
Peaceful (2/10)
Temperature
✓ Compatible
Honey Blue Eye
20–28°C
Mountain Rainbowfish
17–24°C
pH Range
✗ No overlap
Honey Blue Eye
4.5–7
Mountain Rainbowfish
7.4–8.5
Hardness (dGH)
✓ Compatible
Honey Blue Eye
1–8
Mountain Rainbowfish
8–20
Water Type
✓ Compatible
Honey Blue Eye
Freshwater Only
Mountain Rainbowfish
Freshwater Only
Flow Preference
✗ No overlap
Honey Blue Eye
Low
Mountain Rainbowfish
High
Min Tank Volume
Combined: 110 L
Honey Blue Eye
40 L
Mountain Rainbowfish
110 L
Swimming Level
Shared: 2 zones
Honey Blue Eye
TopMiddle
Mountain Rainbowfish
TopMiddle
🏷️Behavior Tags
Honey Blue Eye
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)Shy / Slow Moving (Easily Stressed)
Mountain Rainbowfish
Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Stocking calculator

Can your tank handle Honey Blue Eye and Mountain 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.

Honey Blue Eye
Mountain Rainbowfish
Test both in my tank

Behaviour & Temperament

Both Honey Blue Eye and Mountain 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.

Honey Blue Eye and Mountain Rainbowfish both frequent the Top (Surface) and Middle (Open Water) 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: Honey Blue Eye is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 20°C and 24°C. Aim for the midpoint of this range (around 22.0°C) for optimal comfort.

The pH requirements of Honey Blue Eye (4.5–7) and Mountain Rainbowfish (7.4–8.5) do not overlap, making it impossible to satisfy both species simultaneously.

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

Tank Setup

To house Honey Blue Eye and Mountain 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.

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). Meeting these requirements will help both species thrive.

Honey Blue Eye prefers Low (Still Water) flow while Mountain 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 Usually Fails in Practice

Honey Blue Eye and Mountain Rainbowfish 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 Honey Blue Eye and Mountain Rainbowfish.

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Frequently Asked Questions

Can Honey Blue Eye and Mountain Rainbowfish live together?

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

What size tank do Honey Blue Eye and Mountain 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 Honey Blue Eye and Mountain Rainbowfish together?

Keep the aquarium between 20°C and 24°C. A target of around 22.0°C sits comfortably within both species' preferred ranges.

Are Honey Blue Eye or Mountain Rainbowfish aggressive?

Honey Blue Eye is peaceful (2/10) and Mountain Rainbowfish is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Honey Blue Eye and Mountain Rainbowfish need?

Their pH requirements do not overlap. Honey Blue Eye prefers 4.5–7, while Mountain Rainbowfish needs 7.4–8.5. This makes them incompatible in the same water chemistry.

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?
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