Building a backyard fish pond requires thorough planning to prevent problems during and after installation. Planning includes pond placement, shape and design, and consideration of the pond's biological and technical requirements.
Measure the area of your backyard where you would like to build the pond. Leave enough space for other activities.
Draw the square outline of the pond area on a sheet of graph paper. The scale will depend on the size of your pond. For small ponds, each square on the graph paper can represent 3 inches. For larger ponds, they could represent 1 foot.
Decide if you want the pond to be in-ground or above ground. In-ground ponds are cheaper to build because they don't require supports like bricks or blocks. However, they require a lot of work and result in soil that either needs to be used elsewhere or hauled away.
Decide if your pond will need aeration and filters. If you want filtration, sketch the location of the nearest outdoor electrical supply and a likely path for the line to the filter. If you are building an above-ground pond, sketch a small area to store the pumps and filters. If you are building in-ground pond, plan to dig a small area to hold the pumps and filters.
Sketch the approximate location of decorative rocks and plants.
If you are building an above-ground pond, measure the size of the bricks or blocks and estimate the number required for the perimeter. Multiply that number by the number of courses required to bring the pond to the desired height to get an estimate of the blocks or bricks required.
Make a materials list, including any required pipes and tubes and lengths of conduit and electrical cable to provide power to the pumps. If you are using rocks for the pond base, include a bag or two of masonry cement to hold the rocks together. Include the pond liner, which can be pre-shaped or custom-made.