My fish have very vivid imaginations. There is absolutely nothing in the tank...it's bare bottom, undecorated, yet they manage to spook themselves and freak out running away from some imagined predator. They only come to their senses when they slam into a tank wall or a tank lid. They hit so hard, they usually have a cut or scrape somewhere. They hit with such a loud bang, I used to run to check on them and the tank. Good thing it's an acrylic tank. They hit the lids so hard, they have splashed water 6' away on the living room windows.

