ponds
Hi,
It needs to be deep enough to protect the fish from the sun & so that the water doesn't get to hot. > 75 cm deep if in full sun.
A simple construction method.
Place railway sleepers to form a rectangle. 2 or 3 high for depth. Spread 'shade cloth' out over the pond. Nail the the 'shade cloth' to the sleepers on the outside of the pond on the bottom row, pulling the cloth so that it is relatively tight over the pond. This will make like a hammock suspended over the rectangle. When the cloth is secured (nailed), sheet plastic can be spread out over the 'shade cloth'. The plastic is filled with water. As it fills, it places weight over the shade cloth, pulling the shade cloth tight. The shadecloth then pulls the railway sleepers together. The edges of the plastic can be trimmed.
Add water & add fish food each day, wait a week & then add the fish.
You should investigate the diurnal temperatures of the pond to ensure your fish can cope.
The pond should be cycled if you start a bio-filter. Fish food could be used instead of ammonia.
A submersible pump can pump up to a box (bio-filter) and gravity return it to the pond.
The bio-filter can be a plastic box (>10% of pond volume) filled with matting, bio-balls etc. Plumbing fittings can be purchased for placing a hole in the bottom of the box as a return and a smaller diameter hole for a overflow, both return by gravity to the pond.
Other fittings can be used to make a spray bar, at the top of the box for the filter inlet, costs about $120.00 Aus for filter & pump.
Most lfs sell these filters, so have a look & then build your own for less money.
Plastic liner costs $1.10 per metre in Western Australia. Thats all I use & its cheap to replace. Double or treble the the layers of liner if it is thin sheet plastic. Or purchase a proper liner.