Can Clown Killifish and Severum Live Together?

🟢Ideal Tank Mates

Yes, Clown Killifish and Severum are ideal tank mates. Both species share compatible water parameters and peaceful temperaments, making them well-suited for a community aquarium. They occupy different areas of the water column, which reduces competition for space. A minimum tank size of 336 litres is recommended.


At a Glance

Clown Killifish

Epiplatys annulatus

Severum

Heros severus

🐠Family Group
Clown Killifish
Killifish
Severum
Cichlids - South American
Temperament
Clown Killifish
Peaceful (2/10)
Severum
Semi-Aggressive (5/10)
Temperature
✓ Compatible
Clown Killifish
23–27°C
Severum
24–29°C
pH Range
✓ Compatible
Clown Killifish
5–7
Severum
6–7.5
Hardness (dGH)
✓ Compatible
Clown Killifish
1–8
Severum
4–15
Water Type
✓ Compatible
Clown Killifish
Freshwater Only
Severum
Freshwater Only
Flow Preference
✓ Compatible
Clown Killifish
Low
Severum
Moderate
Min Tank Volume
Combined: 336 L
Clown Killifish
19 L
Severum
280 L
Swimming Level
✓ Different zones
Clown Killifish
Top
Severum
MiddleBottom
🏷️Behavior Tags
Clown Killifish
Nano / Bite-sized (Predation Risk)Jumper (Lid Required)Shy / Slow Moving (Easily Stressed)Fry Predator
Severum
Plant DestroyerTerritorial (Defends specific area)Digger (Disturbs Substrate)

Behaviour & Temperament

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

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

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.

Both fish can tolerate a pH between 6 and 7. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 4–8 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Clown Killifish and Severum together, plan for an aquarium of at least 336 litres with a minimum length of 120 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: Plants - Floating, Plants - Densely covered, Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Severum is a plant destroyer, which conflicts with Clown Killifish's requirement for live plants. Compromise where possible or prioritise the more critical need.

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

Find the right tank equipment

Browse tanks, décor, and equipment suited for this setup.

Frequently Asked Questions

Can Clown Killifish and Severum live together?

Yes. Clown Killifish and Severum are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.

What size tank do Clown Killifish and Severum need?

A minimum of 336 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 Clown Killifish and Severum 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 Clown Killifish or Severum aggressive?

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

What pH do Clown Killifish and Severum need?

Both species overlap in the 6–7 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

How do I manage Severum's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Severum 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.


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