Moving towns is simple,
here is the part of Carl's Guide which describes how to move towns. Just scroll down to the part with the three 'options' and it describes how to move the whole family plus the house or just the family to the new town, as well as how to take all their belongings with them.
About the deathfish in Bridgeport, you find them in the pond at the cemetery in Bridgeport, but you can only catch them after midnight.