Originally Posted by DDPP

It all depends on density of your body vs. the surrounding water. If it's high/low you would be more affected by gravity than if it is low/high, or both were the same.

For example, if you lived in water and had an air-filled bladder (like most bony fish), the gravity wouldn't matter. The bladder would allow you to control how dense you are relative to the surroundings (by compressing it or relaxing it), and therefore how much you "weigh". If you were a human and the water was REALLY salty (like in the black sea) you would actually float to the surface. If it was fresh water, you could sink to the bottom, but gravity wouldn't affect you too much because most of your body is made out of water.

... so in general, you're right. Gravity wouldn't have such a big impact underwater on life as we know it.