Compatibility brief
Can Oscar live with Swordtail?
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 Swordtail (about 12cm) once grown. Plan around adult sizes, not shop sizes.
Temperament gap (aggressive vs semi-aggressive) adds stress on top of the hard incompatibility — space and cover do not make this pairing safe.
Assessment details
Compatible temperature range
Both fish can comfortably share similar water temperatures.
“Oscar (35cm) is predatory and Swordtail (12cm) is small…”
Oscar may eat Swordtail
Next steps
Concrete changes, not "research more" filler.
- •Provide plenty of hiding spots and visual breaks so Swordtail can escape if harassed.
- •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. Xiphophorus hellerii
Supports: aquarium size, water chemistry, temperament and compatibility (primary care reference).
- FishBase. Xiphophorus hellerii
Supports: taxonomy and wild maximum size — translate to tank stocking, not a target number.
- Wikipedia. Xiphophorus hellerii
Supports: general species background and common-name orientation only.
Try this next
Build the full stocking list with Oscar + Swordtail
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.