Can Asian Upside Down Catfish and Clown Killifish Live Together?

Not Recommended

Asian Upside Down Catfish and Clown Killifish are not recommended as tank mates due to 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

Asian Upside Down Catfish

Mystus leucophasis

Clown Killifish

Epiplatys annulatus

🐠Family Group
Asian Upside Down Catfish
Catfish
Clown Killifish
Killifish
Temperament
Asian Upside Down Catfish
Aggressive (8/10)
Clown Killifish
Peaceful (2/10)
Temperature
βœ“ Compatible
Asian Upside Down Catfish
23–27Β°C
Clown Killifish
23–27Β°C
pH Range
βœ“ Compatible
Asian Upside Down Catfish
6–8
Clown Killifish
5–7
Hardness (dGH)
βœ“ Compatible
Asian Upside Down Catfish
5–20
Clown Killifish
1–8
Water Type
βœ“ Compatible
Asian Upside Down Catfish
Freshwater Only
Clown Killifish
Freshwater Only
Flow Preference
βœ“ Compatible
Asian Upside Down Catfish
Moderate
Clown Killifish
Low
Min Tank Volume
Combined: 380 L
Asian Upside Down Catfish
380 L
Clown Killifish
19 L
Swimming Level
βœ“ Different zones
Asian Upside Down Catfish
MiddleBottom
Clown Killifish
Top
🏷️Behavior Tags
Asian Upside Down Catfish
Piscivore (Eats small/nano fish)NocturnalGenerally AggressiveAggressive to same species/look-alikesTerritorial (Defends specific area)Shrimp Eater
Clown Killifish
Nano / Bite-sized (Predation Risk)Jumper (Lid Required)Shy / Slow Moving (Easily Stressed)Fry Predator
Stocking calculator

Can your tank handle Asian Upside Down Catfish and Clown Killifish?

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.

Asian Upside Down Catfish
Clown Killifish
Test both in my tank

Behaviour & Temperament

Asian Upside Down Catfish is a semi-aggressive species (8/10), while Clown Killifish is peaceful (2/10). This notable difference means Asian Upside Down Catfish may occasionally assert dominance over Clown Killifish.

Large aggression gap (6 points) between Asian Upside Down Catfish and Clown Killifish increases stress risk for the more peaceful fish.

In terms of spatial distribution, Asian Upside Down Catfish 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.

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 β€” piscivorous fish will prey on nano-sized tank mates..

Additional behavioural considerations to keep in mind: Aggressive fish may bully and stress shy, slow-moving species. Shrimp eaters may also prey on very small nano fish.

Worth noting: Asian Upside Down Catfish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Clown Killifish is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 23Β°C and 27Β°C. Aim for the midpoint of this range (around 25.0Β°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 5–8 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Asian Upside Down Catfish and Clown Killifish together, plan for an aquarium of at least 380 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), 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.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Asian Upside Down Catfish and Clown Killifish.

Diet & Feeding

Feeding time deserves special attention with this pairing. Asian Upside Down Catfish is a known shrimp eater and may prey on small invertebrates or nano fish like Clown Killifish.

Frequently Asked Questions

Can Asian Upside Down Catfish and Clown Killifish live together?

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

What size tank do Asian Upside Down Catfish and Clown Killifish need?

A minimum of 380 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 Asian Upside Down Catfish and Clown Killifish together?

Keep the aquarium between 23Β°C and 27Β°C. A target of around 25.0Β°C sits comfortably within both species' preferred ranges.

Are Asian Upside Down Catfish or Clown Killifish aggressive?

Asian Upside Down Catfish is semi-aggressive (8/10) and Clown Killifish is peaceful (2/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Asian Upside Down Catfish and Clown Killifish need?

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

How do I manage Asian Upside Down Catfish's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Asian Upside Down Catfish space to claim a territory without encroaching on the other fish's area. Adding dΓ©cor that divides the tank into distinct zones works especially well.

Does Asian Upside Down Catfish being nocturnal affect compatibility?

Asian Upside Down Catfish is most active after lights-out, which naturally reduces daytime encounters with its tank mate. This can actually be beneficial, as both fish get undisturbed time to feed and explore. Just ensure food reaches Asian Upside Down Catfish during evening hours.


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