Can Blue Back Blue Eye and Electric Blue Hap Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 4, 2026
Not Recommended

Blue Back Blue Eye and Electric Blue Hap are not recommended as tank mates due to incompatible water types 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

Blue Back Blue Eye

Pseudomugil cyanodorsalis

Electric Blue Hap

Sciaenochromis fryeri

🐠Family Group
Blue Back Blue Eye
Rainbowfish
Electric Blue Hap
Cichlids - African
Temperament
Blue Back Blue Eye
Peaceful (2/10)
Electric Blue Hap
Aggressive (7/10)
Temperature
✓ Compatible
Blue Back Blue Eye
22–30°C
Electric Blue Hap
24–28°C
pH Range
✓ Compatible
Blue Back Blue Eye
7–8.5
Electric Blue Hap
7.8–8.6
Hardness (dGH)
✓ Compatible
Blue Back Blue Eye
10–30
Electric Blue Hap
10–25
Water Type
✗ No overlap
Blue Back Blue Eye
Brackish Required
Electric Blue Hap
Freshwater Only
Flow Preference
✓ Compatible
Blue Back Blue Eye
Moderate
Electric Blue Hap
Moderate
Min Tank Volume
Combined: 200 L
Blue Back Blue Eye
38 L
Electric Blue Hap
200 L
Swimming Level
Shared: 1 zone
Blue Back Blue Eye
TopMiddle
Electric Blue Hap
MiddleBottom
🏷️Behavior Tags
Blue Back Blue Eye
Nano / Bite-sized (Predation Risk)Jumper (Lid Required)Hyperactive / Fast SwimmerFry Predator
Electric Blue Hap
Piscivore (Eats small/nano fish)Fry PredatorAggressive to same species/look-alikesTerritorial (Defends specific area)Hyperactive / Fast Swimmer
Stocking calculator

Can your tank handle Blue Back Blue Eye and Electric Blue Hap?

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.

Blue Back Blue Eye
Electric Blue Hap
Test both in my tank

Behaviour & Temperament

Blue Back Blue Eye is a peaceful species (2/10), while Electric Blue Hap is semi-aggressive (7/10). This notable difference means Electric Blue Hap may occasionally assert dominance over Blue Back Blue Eye.

Blue Back Blue Eye and Electric Blue Hap both frequent the 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.

There is a critical concern: the Nano / Bite-sized (Predation Risk) behaviour of one fish directly conflicts with the Piscivore (Eats small/nano fish) trait of the other — piscivorous fish will prey on nano-sized tank mates..

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 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

Both fish can tolerate a pH between 7.8 and 8.5. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 10–25 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 Blue Back Blue Eye and Electric Blue Hap together, plan for an aquarium of at least 200 litres with a minimum length of 120 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: Driftwood (Digestion/Hiding), Sand (Sifters), Smooth Gravel (Sensitive Barbels). 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

Blue Back Blue Eye and Electric Blue Hap 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 Blue Back Blue Eye and Electric Blue Hap.

Show 5 more tank sizes

Frequently Asked Questions

Can Blue Back Blue Eye and Electric Blue Hap live together?

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

What size tank do Blue Back Blue Eye and Electric Blue Hap need?

A minimum of 200 litres (tank length at least 120 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 Blue Back Blue Eye and Electric Blue Hap together?

Keep the aquarium between 24°C and 28°C. A target of around 26.0°C sits comfortably within both species' preferred ranges.

Are Blue Back Blue Eye or Electric Blue Hap aggressive?

Blue Back Blue Eye is peaceful (2/10) and Electric Blue Hap 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 Blue Back Blue Eye and Electric Blue Hap need?

Both species overlap in the 7.8–8.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

How do I manage Electric Blue Hap's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Electric Blue Hap 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 4, 2026
Last updated
May 4, 2026
Issues or corrections?
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