Catfish thrive on pellet food that is rich in nitrogen, phosphorous, and protein. In a large tank, the fish absorb only about half the nutrients, and the rest is left as waste in the water. This nutrient-rich water happens to be perfect for hydroponic agriculture. Already, many catfish farmers are using the filtered wastewater to raise lettuce. But far easier to grow than vegetables are algae. They are also more profitable.
Hematococcus is a type of algae used to make beta carotene, Vitamin A, antibiotics, and pigments that give salmon meat its appealing pink color. These pigments currently sell for about $1,000 per pound or significantly more than the going price of lettuce. The algae grows copiously in the catfish wastewater and at the same time removes many of the problematic nutrients from the water.
Finding a profitable way to clean up their fish tank water may prove to be a boon for both the farmers and Georgia's water quality.