Killing Fish Egg Fungus with a Disinfectant
By Sandra Avant
A disinfectant has the potential to treat fungus on catfish eggs, according to U.S. Department of Agriculture (USDA) research.
Peracetic acid—a stabilized mixture containing acetic acid (concentrated vinegar) and hydrogen peroxide—killed fungus on catfish eggs in a study conducted by toxicologist David Straus, who works at the Agricultural Research Service’s (ARS) Harry K. Dupree Stuttgart National Aquaculture Research Center in Stuttgart, Arkansas. ARS is USDA’s principal intramural scientific research agency, and this research supports the USDA priority of promoting international food security.
Fungal infections in hatchery-reared catfish eggs can result in serious losses. Peracetic acid does not produce any residues that would harm young fish or the environment, according to Straus. At low doses, it safely and effectively breaks down rapidly into harmless residues.
In the United States, the compound is used to disinfect wastewater and sterilize items for hospitals and the food industry, but it has not been used yet for aquaculture. However, in Europe, peracetic acid is considered a safe and effective replacement for banned chemicals and antibiotics. It is used in Germany and Denmark to control fungus and other pathogens on adult fish and is very effective against several parasites.
In a study, Straus and his collaborator from Germany evaluated the effectiveness of five peracetic acid concentrations—2.5, 5, 10, 15, and 20 parts per million (ppm)—in preventing fungus from growing on catfish eggs. Fungal growth was severe in the group that received no treatment, resulting in 11 percent survival compared to 60 percent survival in the group treated with the low rate of 2.5 ppm, which was determined to be a safe treatment.
Straus and his colleagues are conducting toxicity studies in other species of fish to ensure that the compound is safe before treating them.