Do fish have placenta

Answer 1

If you define a placenta as a structure with which a mother may transfer nutrients to its young during their development up to the moment of free-living birth, then yes. For example the common smooth-hound (Mustelus mustelus), a small shark found in the UK is viviparous (gives birth to young instead of laying eggs) and has a placental connection via an umbilical cord to its pups before they are born. Note the starry smooth-hound (Mustelus asterias) also found in the UK has no placental structure but is viviparous, providing for its young via egg sacks. The Dogfish, another UK shark, is not viviparous and its eggs are the "mermaids' purses" we find washed up on the beach.