Almost any pond can be a fish pond, considering that fish of some kind are likely to make their way to a pond whether intentionally introduced or arriving by stream, bird's foot, or neighborly donation. Still, ponds intended for fish cultivation should incorporate best practice design and water-quality elements, which will vary depending on the fish species and the amount being raised.
Fish ponds can be roughly divided into two groups: warm-water and cold-water habitats.
Warm-water ponds are used to raise carp, catfish, bass, sunfish, tilapia, and the like. Cold-water ponds are home to various species of trout and perhaps other cold-water fish such as pike and muskie.
Warm-water ponds are generally shallower and more nutrient rich than cold-water ponds. Requirements for inflows of fresh water and dissolved oxygen are not as high. These ponds should be deep enough not to freeze the crop in winter, and may require aeration devices to keep part of the ice open and add oxygen. Supplemental feed or fertilization may have to be supplied. Protective cover from predatory birds may also be necessary, such as rafts, piers, dead timber and stumps, and manufactured underwater shelters. Protective nets are also used when necessary.
Watershed quality should be maintained to avoid runoff and inflows from contaminated or eroded land, which would create unhealthy water conditions. If fish are being raised for harvest by seine, there should be areas shallow enough to allow successful netting. Drains or other means of water-level drawdown may be required to facilitate harvests, clean outs, repairs, and the like. Methods for water testing should be available, especially for basic conditions such as pH, temperature, ammonia, and dissolved oxygen.
Cold-water ponds for trout and other northern species require different water conditions and structural features. Trout are not going to grow well (or survive) in temperatures exceeding 65 to 70 degrees F. Because these ponds are likely to be located in northern or high-altitude regions, they should be deep enough to provide a sustainable habitat below the ice cover, which may be several feet thick. Where large crops are being raised, winter aeration may be needed to prevent oxygen starvation. In fact, trout require higher dissolved oxygen year-round, making four-season aeration a necessity for large crops. Trout ponds usually feature a constant exchange of fresh water, from springs, stream, or well. Stones are often used to create fish habitat in the deepest part of the pond, for shade and protection from predators. Small crops of trout often can grow on food native to the pond (insects, crustaceans, minnows, etc.) but usually require supplemental feed to put on weight. They are not generally raised with other fish species.
Cold-water fish ponds do share some features with warm-water habitats: submerged cover, predator protection, watershed maintenance, and water-quality monitoring. Both cold- and
warm-water species can be segregated and protected in cages, although this cage culture technique requires the use of supplemental feed.
Adapted from Earth Ponds A to Z, An Illustrated Encyclopedia. See Books page for ordering information.
Topics vary from month to month and provide great information when researching where you want to build a pond, or how to keep it clean. Other areas of interest are pond use for more than swimming, and how to keep fish happy in your pond.