Rentals, condos, and the like will usually have some rules to prevent PANDEMONIUM! It seems other than "no dogs", a popular one is "small breeds only" - say up to 25lbs. This makes some sense, but obviously, ALL situations really boil down to the OWNERS not the PETS. Shitty owners ruin everything, and a dog, cat, or fish really only serve as reflections of the owners and are pretty much blameless.