There are many similarities and differences between fish and cetaceans; some similarities that I can think of right now are that both are aquatic, have fins, and are vertebrates.
they all live in water
No fish are mammals. Mammals are vertebrate animals that nurse their young. Mammals have many characteristics in common such as being warm-blooded, having some hair or fur, and being tetrapods (having four limbs, although in marine mammals these are fins).
they are both multi-cellular
reptiles and amphibians have the most in common
No, fish are not mammals.
Fish are not mammals, they are fish.
No, fish are not mammals.
No, it is a fish
Some whales are classified as mammals. Smaller fish are not
Fish do not give live birth, most mammals do. Fish do not nurse their young, mammals do.
No. Fish are one class of vertebrates and mammals are another. There are no "fish mammals".
No. Both mammals and birds "inherited jaws" from a common reptilian ancestor which ultimately originated in an early fish.
no. it's a type of fish. fish aren't mammals.