Salinity brought up to fast--effects?

[mondavi]

I just wanted to know what effects it might have on the fish? Or what would be the signs that it was brought up to fast? I know its not good. I just wanted to know what would/could happen to the fish:notsure:

 

[elfdoctors]

A rapid increase in salinity would rapidly dehydrate the fish. Saltwater fish are constantly drinking and then are producing a very concentrated urine. (Freshwater fish rarely drink and produce a very dilute urine). If the kidneys are not used to making the concentrated urine, the constant drinking of hypertonic water would produce a large osmotic gradient where water rapidly passed out of the fish into the stomach (or into outside water if there was an open sore). The fish would go into hypovolemic shock and then stop drinking. Death would be from underperfusion of its tissues.
A gradual rise in salinity is much safer.