Ruiz now holds the WBA, WBO, IBO and IBF belts after his seventh round TKO win over Joshua ad Madison Square Gardens.
And with a re-match on the cards, Fury said Ruiz had fast hands which will "always beat AJ".
Fury said: "I looked at Joshua and I seen that he didn't want to be in the ring on the night. He was looking away he had other things on his mind.
"From round one I could see what was going to happen. I looked at Joshua and he didn't have no water, no sweat walking into the ring, I thought this guys is going to get knocked out. "
Fury may have dissed Joshua by fat shaming Ruiz, but Fury was hardly a picture of health himself not long ago. After a doping ban, Fury hit the beer and 180kg.