Yes it can. How close is the tank to the door. Quick and sudden movements can startel and stress fish. Stressed fish are more prone to desease. If not desease then perhaps brain damage from hitting the glass. LoL. Repeated hitting the glass can also lead to a nasty chin scar/bump.
might sounds kinda wierd, but i like the way my reds look when they get those bumps on thier chins. It happens very rarely, but when they do get them its gives em a meaner look, thier lower jaw jutts out more, and they just look cooler IMO.
Sorry for butting in but I have a suggestion. I had a fishtank by a door opening and like you said when someone entered the room the fish would jump or dive into the end of the tank.
What I did was buy some black card and blacked out the side of the tank which was near the door, this not only stopped them from seeing people enter the room but also mirror'd the tank more so the fish could see themselves which I think also helped.
hey that's actually a really good idea, i might go get some cardboard and cut it down to size, then spraypaint it black.. or put some of that nifty aquatic background paper on it you can buy at petco.. thanks for the suggestion