Remove everything from the bathroom.
Mask the sink, tub and toilet. using painter's tape. Using a roller, paint the ceiling and 2 feet down the walls in the lightest shade of blue. Quickly overlap the lighter blue with the medium blue while the paint is still wet so the colors blend at the edges. Paint halfway down the walls with the medium blue, then repeat the process with the cobalt blue, painting the remainder of the walls down to the floor for an under-the-sea graduated paint scheme. Touch up any missed spots and the corners with the paintbrush.
Measure the floor to the ceiling carefully. Cut two porch columns to fit on each side of the bathtub. It is not necessary to keep them perfectly vertical; install one or both at an angle to generate the feeling of the undersea disaster of a fallen Atlantis.
Screw tiny eye hook screws into the ceiling, scattered in groups of three or five. Touch up with the light blue paint so they fade into the "sky." Hang plastic goldfish at varying heights with the fishing line. To make a hole in the top fin for hanging, heat an upholstery needle with a lighter until red hot, then push through the plastic. Experiment with the first one or two to ensure that the goldfish hang on the level before preparing the rest of the goldfish for hanging.
Juxtapose elements of your surrealist dreams. Put a ceramic goldfish vase inside a Greek-style white bowl and surround it with oranges. Place the bowl and its contents on top of the toilet tank. Alternately, place a reproduction of the Venus de Milo on a shelf with goldfish "swimming" in mid-air around it.
Hang an assortment of vintage and modern clocks on the walls. Use a variety of shapes and colors. Hang a reproduction of the classic Felix the Cat clock across from the bathroom mirror.
Attach two or three goldfish drain stoppers to the wall among the clocks, so they are "swimming" out of the room.
Incorporate other surreal elements, such as a palm trees or cast iron plants, ceramic figures, stuffed toys, art prints and an orange or pebble-look rug.
Hang a clear plastic shower curtain so your surrealist vision is visible to all.