How do ocean fish survive in salty water?
Marine fish live in a salty (hypertonic) environment, and they tend to lose water to the environment by osmosis. Water losses are replaced by drinking, but drinking salt water introduces more solutes (salt) which must be gotten rid of. So, ocean fish have adapted to salty water in a few ways – e.g. getting rid of solutes by active transport through gills, water loss by osmosis through the gills, and minute amount of urine containing solutes eliminated by kidneys.
