Due to no jaws, no paired fins and scales on the body.
Explanation:
Pteromyzon fish is different from scolidon and labeo fishes because Pteromyzon fish is not a true fish. The main reason for this is that Pteromyzon fish is agnathous means having no jaws and it doesn't have paired fins and scales on their body while all these features are present on the body of scolidon and labeo fishes so we can conclude from this discussion that Pteromyzon fish is different from scolidon and labeo fishes.
