Interesting...
I know that light would change from day to night of course..but how much does the current, and wave action, actually change during this period in the natural environment (or does it?)
If it doesn't: do the fish find a calmer area at night due to the fact they usually have the room to do so?
If it does: would this not be caused, in part by winds, due to heating and cooling of land masses, in which case the decision would be made by what type of fish we have due to their local environment being near or far from land masses?
Just wondering about why the decision comes about...
Billb