Compatibility Report
GuideMyTank compatibility analysis for Oscar and Ranchu Goldfish.
Planning verdict
incompatibleDo not plan a shared aquarium for this pair. Choose a different tank mate or maintain separate aquariums.
No automatic safety blocker was found.
Oscar and Ranchu Goldfish receive a not recommended verdict from the current structured assessment. Oscar is recorded as aggressive with an aggression level of 6/10; Ranchu Goldfish is recorded as peaceful with an aggression level of 1/10. The recommendation is based on the combined water, space, behavior, grouping, and predation checks below rather than on species names alone.
Oscar has a recorded temperature range of 74–81°F and pH range of 6–7.5. Ranchu Goldfish is recorded at 65–75°F and pH 7–8. Their shared planning window is 74–75°F for temperature and 7–7.5 for pH. A shared aquarium must stay inside the overlap rather than merely touching each species’ outer tolerance.
Oscar sets the larger listed base aquarium requirement at 75 gallons; the other listed minimum is 30 gallons. Oscar is the larger adult by the recorded maximum, reaching 14 inches, compared with 8 inches. These figures are starting constraints, not a stocking-capacity calculation, because the complete group sizes and bioload still matter.
Oscar is a moderate species associated with the mid zone and moderate flow. Ranchu Goldfish is calm, uses the mid zone, and has a low flow preference. Oscar does not have a recorded minimum school larger than one, while ranchu goldfish does not have a recorded minimum school larger than one. The aquarium must support both social structures without forcing either species into insufficient space.
Oscar is recorded as a carnivore with intermediate care, while Ranchu Goldfish is a omnivore with advanced care. Their listed preferred tank styles are predator and goldfish. Feeding access, cover, open swimming room, filtration, and observation should be planned around the more demanding requirement rather than averaged between the two species.
Use these pair-specific boundaries before treating the verdict as an acceptable stocking plan.
Do not plan a shared aquarium for this pair. Choose a different tank mate or maintain separate aquariums.
These references support the underlying species records used by this assessment. They do not necessarily evaluate this exact pair together.
Continue with the most relevant care and compatibility resources for Oscar and Ranchu Goldfish.