If you feed the fish well, they are more likely to be full and less likely to eat each other. However, well fed fish will want to breed and that can cause lots of aggression, especially among cichlids. Less food or feeding less often will reduce their urge to breed, and reduce aggression.
Feed a dry food first and then feed frozen food. If you have live food, put that in the tank after the dry and frozen food. You can feed frozen and live food every day but give them dry food first.
If you feed them well every second day, they will be fed but hopefully won't want to breed as much. However, baby fish and young fish need to be fed well every day so they can grow. If they aren't fed well, they won't grow as fast or at all.
When it comes to adding food to the tank (assuming it is cycled with an established biological filter), feed a small amount of food and let the fish eat it. If they eat it all in a few seconds, offer them a bit more. They should eat everything within a couple of minutes. Uneaten food should be removed after 5-10 minutes unless you have catfish or loaches that should come out when they smell the food.
In this case, I would feed dry food for a couple of minutes, then offer frozen food. They will eat more than 2 cubes of frozen fish food each day. Frozen food can be offered 1 or 2 cubes at a time, one cube at a time is probably safer until you know how much the fish can eat. They should eat all the frozen food within a couple of minutes.