How much room does an Oscar fish need?

Oscars can grow up to 12 inches (30.5 cm) in length and require at least a 50-gallon (189-liter) tank. However, a larger tank of at least 75 gallons (284 liters) is recommended to provide them with more swimming space and to accommodate their active nature. Oscars are messy fish and produce a lot of waste, so a high-quality filtration system is also essential.