Bottlenose dolphins, like all mammals, do not undergo metamorphosis. Metamorphosis is a series of dramatic physical changes that some organisms, like insects, amphibians, and some fish, go through during their life cycle. During metamorphosis, the juvenile stage of the organism looks very different from the adult stage, and the body undergoes significant changes in order to adapt to the adult lifestyle.
Bottlenose dolphins, however, are mammals, and they give birth to live young that look like miniature versions of the adults. They do not go through a distinct larval or juvenile stage with a different body structure. Instead, they grow gradually from birth to adulthood, without major physical transformations.