Duckweed for Fish Food

     Fish food is by far the largest input in an aquaponic system.  Whether your goal is to save money or to have a more self-sustained aquaponic system, producing food for your fish is a must.  Even producing fish food to supplement a commercial feed can significantly reduce the amount of commercial feed needed to maintain a well balanced system.  One of the best options available is to produce your own duckweed.
     Duckweed is a small aquatic plant that grows on the surface of slow moving waterways or ponds.  It is the smallest flowering plant currently known to many and lacks stems or leaves.  When grown in ideal conditions duckweed can contain between 35-45% protein.  It also contains trace minerals and pigments.  The high protein content combined with the fact that duckweed can double in size every 48 hours makes duckweed a great choice for a sustainable fish feed supplement. 
     Growing duckweed isn't hard.  It requires adequate sunlight, moderate temperatures, and nutrient rich water.  Currently Trinity Aquaponics is experimenting with growing duckweed in water flushed from aquaponic systems.  The idea is to recycle the water flushed during maintenance to produce another useful crop instead of simply dumping the water out.  As we get results from the experiment I'll keep you posted on how things are going.  More information on growing duckweed can be found on eHow.