Lack of Zinc in diet. Rare.
Validation: Test whole blood or serum for zinc levels. Levels of 7-9 ppm are indicative of gross deficiency.
Fair to good if dietary zinc is increased.
Improve water quality, keep bottom of tanks clean, reduce stock density.
Dr. Ramseyer, Laurel
Dept. of Fisheries & Wildlife
Michigan State University
East Lansing MI USA