Aflatoxicosis is a disease fish contract after eating molded, contaminated feed. Improper storage is a leading cause of aflatoxin-producing molds. Major swings among temperatures, humidity levels, and moisture levels in feed make our region a prime candidate for such conditions.
According to research at the University of Florida IFAS Extension service, affects of the disease vary with fish species and age. Fry are more susceptible to aflatoxicosis than adults. Some species are more vulnerable than others. Initial symptoms are pale gills, anemia, poor growth rates or poor weight gain. Aflatoxins depress the immune system, making fish more susceptible to bacterial, viral, or parasitic diseases.
Feed should be stored off the ground on pallets and at least one-foot from any walls to avoid condensation. Keep in a cool, dry area no longer than three-months. Scientists recommend not storing feed in outside bins longer than two-weeks. When feeds are stored for long periods or under poor conditions, fish health problems may arise from not only molds, but vitamin loss and rancid oil among feed ingredients. Products stored for long periods and potentially contaminated with molds appear stale, discolored, lump together, and smell musty. Stale foods often are saturated with moisture and appear to sweat. Containers, including automatic feeders, should be cleaned regularly and thoroughly. Mold may grow on surfaces and be hidden by new, fresh pellets. Watch for blue/grey mold on feed. To prevent aflatoxicosis, follow manufacturer’s recommendations regarding shelf life and attempt to determine feed production date.
Deer hunters and folks who feed pet deer should be aware of aflatoxin. It’s also common in corn.