I agree with most of the rest, in general, dog hands down...but i have seen some pretty damn personalityless dogs, and had some fish with a lot of damn personality as well.... hell my oscar used to swim around my hand when I was moving things in his tank, and made sure that no other fish dare come near me, thing was like a guard dog. Chased all the others away when they did come near. That fish had more personality than some dogs i have seen, and one dog that i have had...so its an individual thing...but dogs win personality, if i had to choose between dog and fish though....FISH!