It's 2019 can we please stop the stupid?

[Brian37]

Dolphins are also fish.  This is a dolphin fish:



Boru

That is a layperson's name, not a scientific definition.

For a dolphin to be both a mammal and a fish it would have to have BOTH lungs and gills and lay eggs and give live birth, and we both know dolphins do not have both or do both. 

"Dolphin fish" in the case of this picture is a laypersons name, not a scientific classification.

If the species pictured in this post lays eggs it is a fish. If it has gills it is a fish.

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"Dolphin fish" is the name of a different species, not the scientific classification of mammal.

The other dolphin, the ones with lungs who gives live birth is a mammal water, but not a fish.