Compatibility brief
Can Clown Killifish live with Oscar?
Risky. This mix is commonly discouraged for typical setups.
Clown Killifish + Oscar: Aggression mismatch. Oscar is aggressive, while Clown Killifish is peaceful. The aggressive fish will likely bully or harm the peaceful one. Real tanks add variables Fishori cannot model; treat this as a high-risk read, not certainty.
Compatibility score
Profile confidence: low
Order of checkstank volume vs adults → predation mouth gap → temperament / fin nipping → shared water windows.
300L
Combined minimum footprint reference for these two species: about 300L (larger active fish often want more length).
Oscar (35cm adult) may treat small Clown Killifish (~3.5cm) as food once grown — plan adult sizes, not shop sizes.
Clown Killifish (peaceful) and Oscar (aggressive) are far apart on aggression — bullying or injury is a common outcome in average community layouts.
Assessment details
Aggression mismatch
Top issueOscar is aggressive, while Clown Killifish is peaceful. The aggressive fish will likely bully or harm the peaceful one.
Oscar may eat Clown Killifish
Oscar (35cm) is predatory and Clown Killifish (3.5cm) is small enough to be eaten. This pairing is unsafe.
Compatible temperature range
Both fish can comfortably share similar water temperatures.
“Oscar is aggressive, while Clown Killifish is peaceful”
Aggression mismatch
Next steps
Concrete changes, not "research more" filler.
- •Clown Killifish should be kept in a group of at least 6 for best health and behaviour.
Try instead
- →Clown Killifish should be kept in a group of at least 6 for best health and behaviour.
- →Build a species-only tank for the larger fish, or restock with fish too large to be eaten at adult sizes.
- Seriously Fish. Epiplatys annulatus
Primary: species page covering West African blackwater origin, soft water needs, and the rocket-like swim pattern.
- Practical Fishkeeping. Clown Killifish Profile
Secondary: editor write-up on tank-bred lines, feeding strategy (micro-pellets, BBS), and shrimp-tank compatibility.
- Seriously Fish. Astronotus ocellatus
Primary: aquarium size, water chemistry, behaviour, and compatibility (URL verified in upgrade script; recheck if site content changes).
- FishBase. Astronotus ocellatus
Secondary: taxonomy, distribution, and maximum length in nature; cross-check with aquarium import lines and measured tank parameters.
- Wikipedia. Astronotus ocellatus
Secondary: general species context; verify all husbandry numbers against a dedicated aquarium care sheet and your test kit, not a single table row.
- Wikipedia. Astronotus ocellatus (oscar)
Encyclopaedia overview; use specialist aquarium sources for your stock's real temperature/pH/footprint needs.
Try this next
Build the full stocking list with Clown Killifish + Oscar
Plan further
Try both species in the full-stock tank check, or open either fish profile for mates lists. Methodology explains how verdicts are produced.
Individual fish vary in personality. Fishori uses conservative hobby rules. Observe any new introduction closely, feed thoughtfully, and keep a quarantine or backup plan. This is not veterinary advice.
Profile data confidence: medium. Driven by the lower-confidence profile (Clown Killifish): Based on typical aquarium care sources; details may vary between setups.