Is the cod fish a mammal?

No, cod fish are not mammals. They are fish, which belong to the class Actinopterygii.

Here's why:

* Mammals are warm-blooded animals that have fur or hair, give birth to live young, and nurse their offspring with milk.

* Fish are cold-blooded animals that live in water, breathe through gills, and have scales.

Cod fish clearly fit the description of a fish, not a mammal.