In both cases the quality of water is heightened for the individual; that relates to sensitivity, compassion and depth of emotions. Elementally Cancer is of the cardinal nature and expresses more through the emotions and creativity, especially as it relates to family and genetic bonds. They are motivated by emotions which serve to stimulate their actions.
Depending on aspects they can be highly sensitive and prone to moodiness when emotions go awry. Cardinal is naturally a leader type aiming to motivate themselves and others. Typically not afraid to begin new projects and see it through to the end.
Scorpio on the other side is of the fixed quality; they tend to follow the lead of the cardinal signs and further up plans with consistency and determination. At the same time they may not be good at finishing up and thereby rely on friends to keep the momentum going. Typically dependable they can also be stubborn and stuck in their ways.
The Scorpio Moon holds power and is concerned with control issues. With Cancer Sun the depth of emotions is more exclusively aimed at family and domestic concerns. The Cancer Sun is supported by the Scorpio Moon to provide follow-up through determined efforts and the sense of power is more specifically directed towards family and domestic concerns.
Pisces is mutable; typically quite flexible and adaptable, but also prone to vascillation and indecision. The energy wants to feel connected with others and generally has no difficulty making friends with others.
The Pisces Sun with Scorpio Moon is apt to be intense and psychically sensitive. The sense of power can be directed to humanitarian needs, but holding steady will require more earthy factors to support it. Can have a heightened psychic sensitivity.