Biologic evolution

A rare mussel was found.
It seems that it was in the same place as the corbicula. (estuarine
water)There seems to be no skin.
The one like the hair has grown in the entire shell or it seems to
adhere.
The color of the shell is white.
It is a mussel up to now that has not seen.

Is there power to evolve the living thing to the fresh water, and to
change?
It is mysterious.