If gravity was real why don’t the fish, fall to the bottom of the ocean?

When something is in the water, there is a gravitational force in the downward direction and a buoyancy force in the upward direction. If the object is denser than water, gravity wins and the object sinks. If the object is less dense than water, buoyancy wins and the object floats.

They do , once they die.

has to do with density, the ratio of mass and volume. if its less dense than water it floats up to the surface, if its more dense than water it sinks, if its the same it neither floats up nor sinks, like a fish.

They have something called a "swim bladder" that helps them maintain their buoyancy.

They are neutral with respect to the water.

Archimedes

Good question

🤦‍♀️

How can you be sure they don't swim up then fall back down??

It must be the water.