Permitted and Prohibited Aquatic Creatures
Where this fits in the story: Participates in the same pre-Sinai clean/unclean and creation-order world as the land-animal section.
Where Scripture takes it next: Mark 7 and Acts 10 address food/clean-unclean questions at a broader level but do not isolate aquatic creatures.
Evidence boundary: No warranted NT or Christological symbolism is attached to fins/scales themselves.