Can Electric Blue Hap and Threadfin Rainbowfish Live Together?
Electric Blue Hap and Threadfin Rainbowfish are not recommended as tank mates due to conflicting pH requirements 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
Can your tank handle Electric Blue Hap and Threadfin 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.
Behaviour & Temperament
Electric Blue Hap is a semi-aggressive species (7/10), while Threadfin Rainbowfish is peaceful (1/10). This notable difference means Electric Blue Hap may occasionally assert dominance over Threadfin Rainbowfish.
Large aggression gap (6 points) between Electric Blue Hap and Threadfin Rainbowfish increases stress risk for the more peaceful fish.
Electric Blue Hap and Threadfin Rainbowfish 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 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.
Worth noting: Threadfin Rainbowfish 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.
The pH requirements of Electric Blue Hap (7.8–8.6) and Threadfin Rainbowfish (5.5–7.5) do not overlap, making it impossible to satisfy both species simultaneously.
For general hardness, the shared comfort zone is 10–12 dGH. Regular testing will ensure conditions stay within this range.
Tank Setup
To house Electric Blue Hap and Threadfin Rainbowfish 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: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Plants - Densely covered, Plants - Floating. 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
Electric Blue Hap and Threadfin 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 Electric Blue Hap and Threadfin Rainbowfish.
55 Gallon Standard
60 Gallon Breeder
75 Gallon Standard
90 Gallon Standard
125 Gallon Standard
150 Gallon High
Frequently Asked Questions
Can Electric Blue Hap and Threadfin Rainbowfish live together?
No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.
What size tank do Electric Blue Hap and Threadfin Rainbowfish 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 Electric Blue Hap and Threadfin Rainbowfish 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 Electric Blue Hap or Threadfin Rainbowfish aggressive?
Electric Blue Hap is semi-aggressive (7/10) and Threadfin Rainbowfish is peaceful (1/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.
What pH do Electric Blue Hap and Threadfin Rainbowfish need?
Their pH requirements do not overlap. Electric Blue Hap prefers 7.8–8.6, while Threadfin Rainbowfish needs 5.5–7.5. This makes them incompatible in the same water chemistry.
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.
Shared setup supplies
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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?
- Contact the editorial team
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