Lack of Methionine in diet.
Species principally affected: Family Salmonidae, (Atlantic Salmon, Rainbow & Lake Trout), also Channel catfish, red sea bream, European Sea Bass.
Cloudy lens is not reversible, but fish may survive: Market value of fish is greatly reduced however. Severe losses can be expected if not diagnosed & remedial action taken. Typical symptoms are extreme emaciation, listlessness, and a greatly reduced resistance to many diseases. In addition food utilisation and FCR ( food conversion ratios), are noticeably reduced.
Ensure that adequate Methionine is included in the diet, at all stages.
Dr. Hughes, Stephen
National Biological Service
Maryland Cooperative Research Unit