Compatibility brief
Can Oscar live with Upside-down Catfish?
Risky. This mix is commonly discouraged for typical setups.
Compatibility score
Profile confidence: medium
How we decideFishori checks adult size and predation risk, behaviour, water requirements and tank needs before giving a verdict.
300L
Combined minimum footprint reference for these two species: about 300L (larger active fish often want more length).
Oscar (about 35cm as an adult) can realistically eat Upside-down Catfish (about 10cm) once grown. Plan around adult sizes, not shop sizes.
Oscar (aggressive) and Upside-down Catfish (peaceful) 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 Upside-down Catfish is peaceful. The aggressive fish will likely bully or harm the peaceful one.
Oscar may eat Upside-down Catfish
Oscar (35cm) is predatory and Upside-down Catfish (10cm) 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 Upside-down Catfish is peaceful”
Aggression mismatch
Next steps
Concrete changes, not "research more" filler.
- •Upside-down Catfish should be kept in a group of at least 4 for best health and behaviour.
- •Oscar reaches ~35cm: tank length and turning room matter more than the litre number. A tall, short tank of the same volume is not equivalent.
Try instead
- →Build a species-only tank for the larger fish, or restock with fish too large to be eaten at adult sizes.
- 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.
- Seriously Fish. Synodontis nigriventris
Supports: aquarium size, water chemistry, temperament and compatibility (primary care reference).
- FishBase. Synodontis nigriventris
Supports: taxonomy and wild maximum size — translate to tank stocking, not a target number.
- Wikipedia. Synodontis nigriventris
Supports: general species background and common-name orientation only.
Try this next
Build the full stocking list with Oscar + Upside-down Catfish
Plan further
Check each species’ mates list, size the glass, then verify the full stock in the builder. 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: high. Checked against several solid care sources that mostly agree.