Can Blue Dolphin (Hap) and Clown Killifish Live Together?

🔴Not Recommended

Blue Dolphin (Hap) and Clown Killifish are not recommended as tank mates due to conflicting pH requirements and incompatible hardness ranges. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Blue Dolphin (Hap)

Cyrtocara moorii

Clown Killifish

Epiplatys annulatus

🐠Family Group
Blue Dolphin (Hap)
Cichlids - African
Clown Killifish
Killifish
Temperament
Blue Dolphin (Hap)
Semi-Aggressive (5/10)
Clown Killifish
Peaceful (2/10)
Temperature
✓ Compatible
Blue Dolphin (Hap)
24–28°C
Clown Killifish
23–27°C
pH Range
✗ No overlap
Blue Dolphin (Hap)
7.5–8.6
Clown Killifish
5–7
Hardness (dGH)
✗ No overlap
Blue Dolphin (Hap)
10–25
Clown Killifish
1–8
Water Type
✓ Compatible
Blue Dolphin (Hap)
Freshwater Only
Clown Killifish
Freshwater Only
Flow Preference
✓ Compatible
Blue Dolphin (Hap)
Moderate
Clown Killifish
Low
Min Tank Volume
Combined: 570 L
Blue Dolphin (Hap)
475 L
Clown Killifish
19 L
Swimming Level
✓ Different zones
Blue Dolphin (Hap)
MiddleBottom
Clown Killifish
Top
🏷️Behavior Tags
Blue Dolphin (Hap)
Digger (Disturbs Substrate)Hyperactive / Fast SwimmerAggressive to same species/look-alikes
Clown Killifish
Nano / Bite-sized (Predation Risk)Jumper (Lid Required)Shy / Slow Moving (Easily Stressed)Fry Predator

Behaviour & Temperament

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

In terms of spatial distribution, Blue Dolphin (Hap) prefers the Middle (Open Water) and Bottom (Substrate) zones, whereas Clown Killifish occupies the Top (Surface) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Clown Killifish 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 27°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

The pH requirements of Blue Dolphin (Hap) (7.5–8.6) and Clown Killifish (5–7) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Blue Dolphin (Hap) needs 10–25 dGH while Clown Killifish requires 1–8 dGH.

Tank Setup

To house Blue Dolphin (Hap) and Clown Killifish together, plan for an aquarium of at least 570 litres with a minimum length of 150 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), Plants - Floating, Plants - Densely covered, Leaf Litter/Blackwater. 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 Clown Killifish live together?

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

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

A minimum of 570 litres (tank length at least 150 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 Clown Killifish together?

Keep the aquarium between 24°C and 27°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Blue Dolphin (Hap) or Clown Killifish aggressive?

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

What pH do Blue Dolphin (Hap) and Clown Killifish need?

Their pH requirements do not overlap. Blue Dolphin (Hap) prefers 7.5–8.6, while Clown Killifish needs 5–7. This makes them incompatible in the same water chemistry.


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