of course food manufacturers are going to tell you to feed three times a day, they obviously want to sell their product.
In the wild, Oscars will reproduce during the rainy season when there is plenty of food around. You can feed an Oscar three times a day until it is up to around 4 inches, then I wouldreduce that to around twice a day. Once they reach approximately 7 inches, you don't need to feed them any more than once a day.Want to Oscar reaches maturity then I would feed it sparingly. Fish can go without food for many many weeks, sometimes months. In the South American rainforests, they have no choice in the dry season when many fish get trapped in the Lakes that have hardly any water in them, let alone food for them to eat. So don't let anyone tell you that fish need to be fed every day, they do not. It is better to under feed a fish than overfeed it.