Fish & Prawns

Aquaponics Fish

When deciding to take on the adventure of aquaponics some thought must also be given to what type of aquaponics fish will be raised in this environment. Some fish are raised for the purpose of eating while others are more ornamental.

There is a wide variety of fish species that can be grown in an aquaponic environment and with the right plant life and other aspects of this ecosystem, fish will grow healthy and strong.

Aquaponics Fish For Eating

The top favored aquaponics fish to be raised for the purpose of eating are tilapia, trout, and bass. Each of these fish species has specific needs that should be adhered to for achievement of best results. Also, you want to make sure that fish you are putting in the water tank are compatible. You would not want to go out and find that some of your fish have been eaten.

Bass

Bass prefer mildly cool water ranging between 15 – 35 degrees with 23 – 30 degrees being the preferred range. The younger fry need water just a tad cooler. Keep in mind that bass are big fish when grown, so you would not want to take on this species of fish if you only have a small area to work with.

Trout

Trout grow to be a descent size when cared for properly. This fish species is a coldwater fish, but is an excellent aquaponics fish because it grows fast. They prefer temperatures around 4 degrees to 26 degrees. During the fry stage, the minimum temperature for trout is 5 degrees.

Tilapia

Tilapia are a warm water fish, and it is recommended to not have water temperature below 12 degrees. If it falls below this margin tilapia become sick and when water is below 10 degrees, they will start dying off.

Aquaponics Fish For Decoration

The best aquaponics fish species for decoration are koi, goldfish, and perch. Many people raise koi for income purposes.

Koi

When possible it is best to purchase koi at an early age when they are not as expensive. There is a tidy little profit that can be made by the raising and sale of this fish species. A few years back a prize koi was sold in Japan for nearly $400,000.00.

Perch

The perch is a very adaptable fish, and makes a good starter fish for aquaponics enthusiasts. Perch come in several colors, but the three most used as aquaponics fish are the yellow, silver, and jade variety.

Aquaponics is an excellent way to get the best of both worlds in fish and plants without chemical interaction. The symbiotic relationship between fish and plant can work to the advantage of the grower by providing food for the table. It may be the fish that was raised, or the plants that benefited from the fish.

For the various species of fish that are used in aquaponics gardening, there are just as many plants that benefit from this closed ecosystem. There are currently over 300 plant species that have been tested and shown success in an aquaponic environment. This is a great hobby for someone to pick up, but is also an excellent learning opportunity. More importantly, it is a great way to ensure that there will always be something to eat for one or for the masses.

Freshwater Prawns

Fresh water prawns may be stocked into concrete and earthen reservoirs, ponds, irrigation ditches, cages, pens and natural waters. Cage and pen culture is experimental, while the production from irrigation ditches is low. Stocking natural waters and reservoirs is called fisheries enhancement. Freshwater prawns are obtained from rivers, or (less frequently) from nurseries, for stocking into open waters. Stocking PL is impractical because most would be lost through predation. Larger juveniles (2-3 g) are usually used for enhancement purposes. The topic of fisheries enhancement is only mentioned here but is described in more detail in New, Singholka and Kutty (2000). This section of the manual deals only with the management of freshwater prawns being reared in earthen ponds.

A freshwater prawn farm is very similar to a freshwater fish farm. A detailed farm design is not provided in this manual because every farm must be unique to its site characteristics. A photograph of a large freshwater prawn farm is given in Figure 43. This section of the manual briefly introduces some general principles of aquafarm development. In doing so, it draws upon some other FAO manuals on site surveying (FAO 1989b), the provision of water supplies (FAO 1981), and farm and pond construction (FAO 1992b, 1995). A simple manual on small-scale freshwater fish farming (FAO 1994) is also available. If you are going to build your own farm, it is highly recommended that you obtain these publications before you develop your farm.

Having selected the site you will need to thoroughly survey it to determine the best layout for water intake, ponds, access roads, and effluent discharge. These topics are not specific to freshwater prawn farms, so there is no attempt here to duplicate the FAO manuals already available, which have been mentioned above. The development of sites for freshwater prawn farming is discussed in detail in Muir and Lombardi (2000).

If you are going to use seining for harvesting, which is often practised in freshwater prawn farming because of the necessity to cull out larger animals (and sometimes to separate females from males, when they have different values) before the final harvest, rectangular ponds are the most suitable shape. The maximum width for this type of management should not be wider than the space through which a seine can be conveniently drawn from one end of the pond to the other by manual labour. A convenient width is 30 m. In practice, of course, wider ponds can also be seined but not so efficiently as narrow ones. The length of the pond depends partly on the topography of the site and partly on the pond size and farm layout chosen. It is best to standardize the width of ponds; otherwise a range of different seine nets will be required for harvesting.

Food and Agriculture Organization of the United Nations