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Freshwater Prawns

Photo by Tom Fisk: https://www.pexels.com/photo/fresh-prawns-3680164/

Let’s dive deep into each step of growing freshwater prawns in an aquaponics system, including growing your own feed and caring for them:

  1. Aquaponics System Setup:
  • Choose a suitable location for your aquaponics system. It should receive plenty of sunlight or use artificial grow lights to ensure plants get the necessary light for photosynthesis.
  • Get a large fish tank or a specially designed aquaponics fish tank. This tank will be the home for your freshwater prawns.
  • Next to the fish tank, set up a grow bed or a hydroponic bed. This is where you’ll grow the plants that will act as the feed for the prawns.
  • Connect the fish tank and the grow bed using a water pump and pipes. The water from the fish tank will be pumped up to the grow bed.
  1. Choosing Freshwater Prawns:
  • When buying freshwater prawns, ensure they are healthy and disease-free. You can get them from a reputable aquaculture supplier or a local hatchery.
  • Common freshwater prawn species globally for aquaponics include Macrobrachium rosenbergii (Giant River Prawn) and Macrobrachium nipponense (Japanese River Prawn).
  • Confirm with the Ministry of Environment and Tourism which species are allowed to grow in Namibia.
  • Make sure the size of the prawns is appropriate for your tank. Juvenile prawns are better suited for smaller systems.
  1. Caring for the Prawns:
  • Maintain a consistent water temperature between 24-29°C. Use a water heater if needed, especially during colder months.
  • Test the water regularly for pH levels, ammonia, nitrite, and nitrate. Ammonia and nitrite should be kept at low levels, while nitrate is the nutrient source for the plants.
  • Ensure good water quality by using a biological filter to convert harmful ammonia into less toxic substances.
  • Perform regular partial water changes (about 20% of the water) to remove excess nutrients and maintain water quality.
  • Avoid overcrowding the prawns as they need space to move and grow.
  1. Growing Feed for the Prawns:
  • Duckweed is an excellent option for prawn feed. It’s a small floating plant that grows quickly and provides essential nutrients.
  • You can also cultivate algae in a separate container and feed it to the prawns.
  • Aquatic plants like watercress, water lettuce, and water hyacinth are also suitable options for prawn feed.
  1. Taking Care of the Plants:
  • Choose fast-growing plants that can efficiently absorb nutrients from the water and provide a continuous food source for the prawns.
  • Regularly trim the plants to ensure they stay healthy and continue growing vigorously.
  • Check for signs of nutrient deficiencies (yellowing leaves) and adjust the nutrient levels in the water if needed.
  1. Checking the Balance:
  • The success of your aquaponics system depends on maintaining a balanced ecosystem. The plants should efficiently utilize the nutrients produced by the prawns, and the prawns should benefit from the clean, filtered water provided by the plants.
  • Keep a close eye on the health of both the prawns and the plants. If you notice any issues, address them promptly to prevent further complications.
  1. Learning and Having Fun:
  • Keep a journal to record observations, water test results, and any changes you make to the system. This way, you can learn from your experiences and improve the system over time.
  • Explore additional resources and books about aquaponics and sustainable farming. The more you learn, the better you can care for your freshwater prawns and create a thriving aquaponics ecosystem.

Remember, aquaponics is a fascinating way to integrate fish and plant cultivation while gaining valuable knowledge about environmental sustainability and natural ecosystems. Enjoy the process of nurturing your freshwater prawns and watching your plants grow!

Here’s an article in the Namibian about growing freshwater prawns.

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