Measure the perimeter of the goldfish pond. You can place the railing immediately next to the pond or place it back a foot or so to put more distance between the viewer and the water. Record the measurement. Purchase one 40-inch and one 26-inch PVC pipe for every 24 inches of the diameter.
Place the 40-inch PVC pipes into the ground around the perimeter of the pond. Use a rubber mallet to hammer the pipes into the ground, spacing them every 24 inches. Drive the pipes into the ground 6 inches deep, leaving 34 inches above the ground.
Apply PVC glue to the top of the PVC pipes using a paintbrush or sponge. Place a three-way PVC connector joint on the top of each pipe. Choose between T-joints, 90-degree angle joints and 45-degree angle joints depending on the shape of the pond. You want the railing to follow the general shape of the pond.
Apply PVC glue to the ends of the 26-inch PVC pipes. Insert the pipes into the three-way joints to create the railings for the pond.