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Compatibility

Compatibility brief

Can Guppy live with Oscar?

Guppy

Guppy

Poecilia reticulata

peaceful~5cm
Oscar

Oscar

Astronotus ocellatus

aggressive~35cm
VerdictRISKY

Risky. This mix is commonly discouraged for typical setups.

Guppy + Oscar: Known incompatible pairing. Oscars are large predators; guppies are bite-sized. This is not a viable long-term community pairing. Real tanks add variables Fishori cannot model; treat this as a high-risk read, not certainty.

Compatibility score

0/100

Profile confidence: medium

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
GuppyOscarShared window
pH
Range6.8–7.8 shared
GuppyOscarShared window
Size / predation

Oscar (35cm adult) may treat small Guppy (~5cm) as food once grown — plan adult sizes, not shop sizes.

Temperament / behaviour

Oscars are large predators; guppies are bite-sized. Any peaceful weeks while the oscar is small end when the mouth catches up. “They grew up together” is not a safety plan for an adult oscar community. This pairing fails on size and diet, not on water overlap alone.

Assessment details

  1. Known incompatible pairing

    Top issue

    Oscars are large predators; guppies are bite-sized. This is not a viable long-term community pairing.

  2. Aggression mismatch

    Oscar is aggressive, while Guppy is peaceful. The aggressive fish will likely bully or harm the peaceful one.

  3. Oscar may eat Guppy

    Oscar (35cm) is predatory and Guppy (5cm) is small enough to be eaten. This pairing is unsafe.

  4. Compatible temperature range

    Both fish can comfortably share similar water temperatures.

“Oscars are large predators; guppies are bite-sized”

Known incompatible pairing

Next steps

Concrete changes, not "research more" filler.

  • •Keep guppies in a peaceful livebearer or community tank. Plan oscar tanks around fish too large to swallow, or keep the oscar as a species fish.
  • •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.
Sources from both profiles
Only URLs that exist on the species records are shown. We do not fabricate citations.
  • Seriously Fish. Poecilia reticulata

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

  • FishBase. Poecilia reticulata

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

  • Wikipedia. Poecilia reticulata

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

  • Wikipedia. Guppy

    Encyclopaedia overview; use specialist aquarium sources for your stock's real temperature/pH/footprint needs.

  • 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 Guppy + 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 Guppy

Guppy + Oscar — common questions

Can Guppy live with Oscar?
For most keepers, no. The verdict is RISKY: adult oscars eat guppies. Do not stock them together in a home tank.
What tank size do you need for Guppy 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's the main risk?
Known incompatible pairing. That is the check that fails outright for this pair. The matching entry under assessment details on this page explains the reasoning and the numbers behind it.
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.