Fish can be startled quite easily. When you approach your aquarium for the first time of the day, or perform maintenance in the tank, don’t move about quickly. Take your time, approach the tank slowly, and move methodically. If a fish gets startled, it may jump out of the aquarium or make a dash for the safety and comfort of the live rock. A fish out of water is obviously not a good thing, but neither is a fish darting around in the aquarium. Live rock can scrape the fish, leading to a physical injury and potentially an infection.