The differences between fold-eared cats and blue cats are as follows:

1. In appearance, blue cats have a rounder body, a larger head, a fat face, and round ears. Upright and upward, with short and thick limbs and thick hair. The ears of folded-eared cats are folded forward and downward, and the face is plump and round.

2. In terms of personality, blue cats are gentle, quiet, and friendly to people. Fold-eared cats, on the other hand, are emotional and playful.

3. Folded-eared cats are a manifestation of cat gene mutation, so cats of any breed may have folded ears. Blue cats can also mate with folded-eared cats to breed folded-eared blue cats.