Midas Cichlid defending his tank

My mother owns this huge 12 inch midas cichlid and he absolutely HATES people standing near his tank. Just walking up the stairs will draw him out of his log to attack. He is in a 40 gallon tall tank. I already know it s too small, but he is not mine so tough bananas for him. :) Oh and by the way the woofing sound you are hearing constantly is my rose breasted cockatoo barking. lol She is a silly