Which fish has the most advanced reproductive methods?

The correct answer is the Seahorse.

Seahorses have the most advanced reproductive methods among fish. The males give birth to live young, and the females do not lay eggs. Instead, the female transfers her eggs to the male's brood pouch, where they are fertilized and develop until they are ready to be born. The male seahorse provides all the care for the eggs and young, including providing them with nutrients from his own body.