But, if this behavior seem abnormal it may be associated with the fish attempting to escape it's environment. Gulping for air at the surface of the water. May be due to low levels of dissolved oxygen, high levels of nitrites or gill parasites. Do a partial water change. Check filtration systems.
Fish can become creatures of habit.
If they are fed at certain times of day each day, their internal clock will tell you it's feeding time by swarming at the place and time of feedings. If one person is the primary feeder, when seeing that person they will swarm to where that person is located. Each fish has it's own personality. I can tell when something is wrong by observing their behavior. When my fish see me they know I will throw some food, so they swarm to where I am and await their treat.