I also feed once a day, but I also have a planted aquarium so I know the fish can nibble on the plants like they would in the wild. Other I know feed multiple times a day. I used to feed in the morning, but now I feed in the evening. If you do feed in the morning, make sure the lights have been on for at least 15 minutes to make sure the fish are awake enough to want to eat.
A rule of thumb is their stomachs are as big as their eye, so don't overfeed no matter how hungry they might look. Also, it is important the quality of food and variety of food you feed them.