Can Blue Dolphin (Hap) and Koi Live Together?

🟢Ideal Tank Mates

Yes, Blue Dolphin (Hap) and Koi are ideal tank mates. Both species share compatible water parameters and peaceful temperaments, making them well-suited for a community aquarium. A minimum tank size of 4542 litres is recommended.


At a Glance

Blue Dolphin (Hap)

Cyrtocara moorii

Koi

Cyprinus rubrofuscus

🐠Family Group
Blue Dolphin (Hap)
Cichlids - African
Koi
Goldfish & Koi
Temperament
Blue Dolphin (Hap)
Semi-Aggressive (5/10)
Koi
Peaceful (2/10)
Temperature
✓ Compatible
Blue Dolphin (Hap)
24–28°C
Koi
4–28°C
pH Range
✓ Compatible
Blue Dolphin (Hap)
7.5–8.6
Koi
6.5–8.5
Hardness (dGH)
✓ Compatible
Blue Dolphin (Hap)
10–25
Koi
4–15
Water Type
✓ Compatible
Blue Dolphin (Hap)
Freshwater Only
Koi
Freshwater Only
Flow Preference
✓ Compatible
Blue Dolphin (Hap)
Moderate
Koi
Moderate
Min Tank Volume
Combined: 4542 L
Blue Dolphin (Hap)
475 L
Koi
3785 L
Swimming Level
Shared: 2 zones
Blue Dolphin (Hap)
MiddleBottom
Koi
TopMiddleBottom
🏷️Behavior Tags
Blue Dolphin (Hap)
Digger (Disturbs Substrate)Hyperactive / Fast SwimmerAggressive to same species/look-alikes
Koi
Hyperactive / Fast SwimmerPlant DestroyerDigger (Disturbs Substrate)Fry PredatorAggressive Eater (Starves shy fish)Jumper (Lid Required)

Behaviour & Temperament

Blue Dolphin (Hap) is a moderately assertive species (5/10), while Koi is peaceful (2/10). This modest difference means Blue Dolphin (Hap) may occasionally assert dominance over Koi.

Blue Dolphin (Hap) and Koi both frequent the Middle (Open Water) and Bottom (Substrate) 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: Koi 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 7.5 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 10–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Blue Dolphin (Hap) and Koi together, plan for an aquarium of at least 4542 litres with a minimum length of 300 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

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). 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.

Frequently Asked Questions

Can Blue Dolphin (Hap) and Koi live together?

Yes. Blue Dolphin (Hap) and Koi are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.

What size tank do Blue Dolphin (Hap) and Koi need?

A minimum of 4542 litres (tank length at least 300 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 Dolphin (Hap) and Koi 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 Dolphin (Hap) or Koi aggressive?

Blue Dolphin (Hap) is moderately assertive (5/10) and Koi is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Blue Dolphin (Hap) and Koi need?

Both species overlap in the 7.5–8.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.


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