for your aro a good mix of hikari food sticks, massovoire, shrimp/prawns, and fish fillets are a great diet...it is a great diet for you cat aswell...DON'T put an oscar in the tank unless you don't care if it gets eatten...everyone who says they have oscars with rtcs and that they are fine are 99.99% of the time wrong...they will at some point eat the oscars...just stick with the big cats of the same size, LARGER silver aro/aros, or pacus like i have been saying from the start...i have had many big cats and will have more...listen to my advice or you will lose fish to consumtion by rtc...
if you notice the guys aro that is being attacked by the rtc, the rtc is bigger...it is only time before it gets caught and the oscars are eatten...it doesn't matter that the grew up together and are "friends"...a guy on here had a massive oscars that grew up with his massive rtcs...onen by one they eventually dissapeared...