AquaStocker

Can a Oscar Live With a Harlequin Rasbora?

Not recommended — a oscar and harlequin rasbora are a risky mix.

Updated June 2026
By the AquaStocker team · How we source our data
Not recommended
OscarOscar
12.0" · 55g min · 74–81°F · Aggressive
+
Harlequin RasboraHarlequin Rasbora
2.0" · 10g min · 73–82°F · Peaceful
Temperatures line up — both thrive around 74–81°F.
pH preferences overlap (6–7.5) — easy to keep both comfortable.
The oscar is big and predatory enough to eat the harlequin rasbora — likely a meal, not a tankmate.
The oscar is aggressive and will likely harass or harm the harlequin rasbora.
Plan on at least 55 gallons for the pair (the larger of their two minimums).

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Aquarium water test kitwatch your parametersAquarium filtermore filtration = headroomAquarium heaterstable temperature55 gallon aquariumroom for both

FAQ

Can a oscar and harlequin rasbora live together?
Not recommended — a oscar and harlequin rasbora are a risky mix. Minimum tank for the pair is about 55 gallons.

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