It is certainly possible that alien life could exist in an ocean planet, either on the surface or beneath it. The idea of life existing in subsurface oceans has gained scientific interest in recent years. In our own solar system, moons like Europa (orbiting Jupiter) and Enceladus (orbiting Saturn) have subsurface oceans that are considered potential habitats for life.
On Earth, we have discovered a diverse range of organisms that can thrive in extreme environments such as deep-sea hydrothermal vents and beneath the icy crust of Antarctica's Lake Vostok. These discoveries have expanded our understanding of where life can exist on our own planet.
Considering the vastness of the universe and the wide variety of environments it encompasses, it is conceivable that life forms could have evolved in different ways, adapted to the conditions of ocean planets, including living beneath the surface. However, without concrete evidence, it remains speculative, and further exploration and scientific investigation are needed to confirm the existence of such life forms.