Can Black Neon Tetra and Blue Back Blue Eye Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 2, 2026
Not Recommended

Black Neon Tetra and Blue Back Blue Eye are not recommended as tank mates due to incompatible water types. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Black Neon Tetra

Hyphessobrycon herbertaxelrodi

Blue Back Blue Eye

Pseudomugil cyanodorsalis

🐠Family Group
Black Neon Tetra
Characins
Blue Back Blue Eye
Rainbowfish
Temperament
Black Neon Tetra
Peaceful (1/10)
Blue Back Blue Eye
Peaceful (2/10)
Temperature
✓ Compatible
Black Neon Tetra
23–28°C
Blue Back Blue Eye
22–30°C
pH Range
✓ Compatible
Black Neon Tetra
5–7.5
Blue Back Blue Eye
7–8.5
Hardness (dGH)
✓ Compatible
Black Neon Tetra
1–15
Blue Back Blue Eye
10–30
Water Type
✗ No overlap
Black Neon Tetra
Freshwater Only
Blue Back Blue Eye
Brackish Required
Flow Preference
✓ Compatible
Black Neon Tetra
Moderate
Blue Back Blue Eye
Moderate
Min Tank Volume
Combined: 54 L
Black Neon Tetra
54 L
Blue Back Blue Eye
38 L
Swimming Level
Shared: 2 zones
Black Neon Tetra
MiddleTop
Blue Back Blue Eye
TopMiddle
🏷️Behavior Tags
Black Neon Tetra
Hyperactive / Fast SwimmerNano / Bite-sized (Predation Risk)
Blue Back Blue Eye
Nano / Bite-sized (Predation Risk)Jumper (Lid Required)Hyperactive / Fast SwimmerFry Predator
Stocking calculator

Can your tank handle Black Neon Tetra 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.

Black Neon Tetra
Blue Back Blue Eye
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Behaviour & Temperament

Black Neon Tetra is a peaceful species (1/10), while Blue Back Blue Eye is peaceful (2/10). This modest difference means Blue Back Blue Eye may occasionally assert dominance over Black Neon Tetra.

Black Neon Tetra 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.

Worth noting: 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 28°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

Both fish can tolerate a pH between 7 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 10–15 dGH. Regular testing will ensure conditions stay within this range.

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 Black Neon Tetra and Blue Back Blue Eye together, plan for an aquarium of at least 54 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, Driftwood (Digestion/Hiding), Leaf Litter/Blackwater, Sand (Sifters). Meeting these requirements will help both species thrive.

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

Why This Pairing Usually Fails in Practice

Black Neon Tetra 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 Black Neon Tetra and Blue Back Blue Eye.

Show 21 more tank sizes

Frequently Asked Questions

Can Black Neon Tetra 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 Black Neon Tetra and Blue Back Blue Eye need?

A minimum of 54 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 Black Neon Tetra and Blue Back Blue Eye together?

Keep the aquarium between 23°C and 28°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Black Neon Tetra or Blue Back Blue Eye aggressive?

Black Neon Tetra is peaceful (1/10) and Blue Back Blue Eye is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Black Neon Tetra and Blue Back Blue Eye need?

Both species overlap in the 7–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

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
Issues or corrections?
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