All foxes are mammals and reproduce internally.
Placental mammals reproduce externally. (not in pouches)
Externally.
internally
internally
externally
External, like most fish.
Female goldfish have ovaries to produce eggs, and reproduce externally. Male goldfish have internal testes, and they also reproduce externally.
Dolphins reproduce internally and give live birth.
internal
Externally fertilize eggs.
The answer really stares you in the face it is internal fertilisation.
Jellyfish reproduce both sexually and asexually.