Discus fish food may consist of a variety of foods, including flakes and pellets, as well as live brine shrimp and black or white worms.
So, which kind of food is best? A mixture of food types works well to give them all the nutrients they need. The simplest and easiest feeding routine would be to stick with dried flakes and pellets (make sure you soak the pellets before introducing them into the tank for your fish so that the pellets don’t expand inside the discus’s stomach). Add some frozen or live food occasionally for variety.
Discus are grazers. They don’t always gobble the food as it drifts to the bottom of the tank. They eat slowly, but often, so they will eat the food that makes it to the bottom of the tank. Therefore, it is important to make sure you keep your aquarium clean, changing out the water on a regular basis. This will remove rotted or decaying food wastes as well as the fecal matter from your discus fish.
Younger fish will need more frequent feedings to grow properly, because their stomach is not as large as the more mature fish.
Beef heart is a common food mentioned around discus discussions. Basically, it’s cheap, and many hobbyists make their own food using beef heart. They simply grind up the beef heart with a mixture of other ingredients, then freeze it in a ziplock bag. At feeding time, a small piece of the frozen mixture is broken off and put into the tank. This mixture may include vegetables and vitamins as well as the necessary protein. It is important to mention that pure protein is not a healthy diet for discus. Beef heart, if used, should be a mixture, not just pure meat.
Live white worms and black worms are also used by some as a food in their tank. These can be obtained from your fish store, or, if you are really ambitious, you can breed them yourself. But this is probably something done by only very dedicated discus keepers.
You do want to be careful not to make your fish sick. Live worms can carry bacteria, heavy metals, and parasites that will wreck havoc in your tank.
Until you are really well acquainted with your discus fish and their requirements, you should stick with food from the fish store. As you become more familiar with the fish, you can experiment with adding different foods to their daily diet.