As said no FEEDERS. Use a good pellet as the staple. Omega one and NLS are the best with hikari cichlid gold coming in a close 2nd. Feed also veggies for a portion of the diet. Around 25%. Give a treat once a week such as frozen blood worms, shrimp, worms, cricket, and my oscars fav.. grasshoppers. Also get some Boyds vitachem liquid vitamins, and soak some freeze dried krill once a week with it by putting some drops on the krill and leaving it for a bit. This is a part of the diet that is essential for good bone development among other things. Vitamin C being the most important for good oscar health. Hopefully you have this oscar in a big enough and not overstocked tank or your just headed for disaster. Lots of large frequent water changes are a must to keep nitrates below 20ppm. I have one oscar in a 125 gallon with silver dollars and need to do 2-3 60-75% water changes a week. Most people don't realize just how important and how much clean water is needed for good health. If your oscar is older than a year, only feed it every 2 days. Over feeding is bad for their health and will shorten their life due to fatty liver disease.