What are the problems for maintaining water balance for freshwater fish and saltwater fish?
In freshwater, water enters the fishes body via osmosis so freshwater fishes have the problem of eliminating excess water and retaining salt. They do this as follows: (their adaptations) 1. They don’t drink water 2. They produce copious amounts of dilute urine. 3. They’re kidneys are adapted to retain as much salt as they can. In saltwater, the opposite takes place and the fishes are adapted to retain as much water and eliminate as much salt as they can. 1. They drink plenty of salt water. 2. They produce very little amounts of concentrated urine 3. They have numerous nephrons in their kidneys which reabsorb as much water as possible into their body. 4. They have special secretory cells in their gills which eliminate excess salt from their body.
