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Compatibility

Compatibility brief

Can Jack Dempsey live with Oscar?

Jack Dempsey

Jack Dempsey

Rocio octofasciata

aggressive~25cm
Oscar

Oscar

Astronotus ocellatus

aggressive~35cm
VerdictGOOD

Often a workable match in a suitable, well-run tank. Still verify behaviour in your setup.

In many setups, Jack Dempsey and Oscar are often kept together in a suitable peaceful community when temperature and pH are matched and the tank is sized for adults. Individual behaviour, filtration, and layout still decide whether it works in your home.

Compatibility score

100/100

Profile confidence: high

Order of checkstank volume vs adults → predation mouth gap → temperament / fin nipping → shared water windows.

Min tank

300L

Combined minimum footprint reference for these two species: about 300L (larger active fish often want more length).

Temperature
Range in °C23–28°C shared
Jack DempseyOscarShared window
pH
Range6.5–8 shared
Jack DempseyOscarShared window

Assessment details

  1. Compatible temperaments

    Both Jack Dempsey and Oscar share a aggressive temperament.

  2. Compatible temperature range

    Both fish can comfortably share similar water temperatures.

Next steps

Concrete changes, not "research more" filler.

  • •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.
Sources from both profiles
Only URLs that exist on the species records are shown. We do not fabricate citations.
  • Seriously Fish. Rocio octofasciata

    Primary: aquarium size, water chemistry, behaviour, and compatibility (URL verified in upgrade script; recheck if site content changes).

  • FishBase. Rocio octofasciata

    Secondary: taxonomy, distribution, and maximum length in nature; cross-check with aquarium import lines and measured tank parameters.

  • Wikipedia. Rocio octofasciata

    Secondary: general species context; verify all husbandry numbers against a dedicated aquarium care sheet and your test kit, not a single table row.

  • 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 Jack Dempsey + Oscar

Compare another pairOpen tank builder

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.

Full tank-mate guides

Related pair checks

Other tank mates for Jack Dempsey

Jack Dempsey + Oscar — common questions

Can Jack Dempsey live with Oscar?
Usually, yes. The pairing resolves GOOD in Fishori's checks for a tank of about 300 litres or more with the shared water windows shown on this page. Individual fish still vary, so watch the first weeks closely.
What tank size do you need for Jack Dempsey and Oscar together?
Plan around 300 litres as the working minimum. That figure comes from each species' published minimum and their group needs, and it assumes adult sizes, not shop sizes.
What should you check before buying?
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.