This is a great long term connection.
Cancer can appreciate this and has no problem giving Scorpio they loyalty they need to feel secure.
Many astrologers have a tendency to match up signs with a similar element: water with water, fire with fire, etc.
Finding ways to be accepting of one another would be challenging, but does offer growth for both parties.
This can lead them straight into Cancer's startled claws.
A Sagittarius partner would support the artistic goals a Pisces often has and not try to force them into conventional ways.