Most people agree that 50 gallons is the absolute minimum size tank for 1 oscar. So yes at a push you could fit a single oscar in that tank. Oscars also require heavy filtration and have high maintenace requirements. Especially in a tank that size.
I have to disagree with Uriel (sorry!) and say no this tank is not big enough for an oscar. 55gal absolute minimum but ideally 75gal is needed, this tank is about 47gal. An oscar 'could' live in it but then my apple snails 'could' live in a soggy matchbox.