Because it gives birth to babies, not eggs
A whale is an Aquatic Mammal NOT a fish. A whale gives live birth and a female whale feeds it's child milk.
It's a mammal: it is warm blooded, gives birth to live offspring, and the mother feeds it's young with mammary glands.
I am pretty sure that the female fish is the fish that gives birth to the baby fish...but I am not sure.
A dolphin is a mammal. It is warm blooded just like all mammals. It gives birth to it's live offspring, not eggs. It feeds its young with milk, like all mammals.
It gives birth
Well firstly a fish can only give birth to 5 babies at the same time. Whales can give birth to greater than 10 babies!
Symbiotic relationship
Swordtail is not a mammal, it's a fish although it gives birth. Another example like Swordtail is Guppy. Guppy gives birth but it's a fish.
Male seahorses are unique in that they carry and give birth to live young, instead of the female. This is the only known example of male pregnancy in the animal kingdom.
Guppies are not the only fish, that give birth. Almost every kind of fish gives birth. However, guppies are pretty easy to give birth. Other fish, such as betta fish, most tropical fish, and angelfish are rather hard to breed, because they are aggressive and will eat their own young. So, I suggest guppies if you want to breed fish.
They have eggs my dad is an expert on fish and he says ''guppys are the only fish who have live babies''