Drug-use Guidance...

Drugs which are forbidden for use in aquatic animals and/or drugs FDA considers to be of high enforcement priority:

The FDA has forbidden the use of certain drugs in all animals or in specific groups of animals. The basis for such decisions are primarily a function of safety to the target animal, the environment or humans who may come in contact with the drug either directly (during the administration of the drug) or indirectly (e.g., via consumption of an animal with drug residues or exposure to effluent water containing the drug).

The following drug is prohibited for use in animal food or feed, and specific government reference can be found at the link noted immediately following the drug.

Gentian violet (= crystal violet) [official government reference]

The following drugs are examples of drugs that FDA considers to be of high enforcement priority (see CVM’s Policy and Procedures Manual #1240.4200 listed below in the Guidance Documents section):

Chloramphenicol
Nitrofurans
Fluoroquinolones and Quinolones
Malachite Green
Steroid Hormones

The following drugs are prohibited from being extralabelled for food-animals, and specific government reference can be found at the link noted immediately following the drug.

Chloramphenicol [official government reference]
Clenbuterol [official government reference]
Diethylstilbestrol (DES) [official government reference]
Dimetridazole [official government reference]
Ipronidazole [official government reference]
Other nitroimidazoles [official government reference]
Furazolidone [official government reference]
Nitrofurazone [official government reference]
Sulfonamide drugs in lactating dairy cattle (except approved use of sulfadimethoxine, sulfabromomethazine, and sulfaethoxypyridazine) [official government reference]
Fluoroquinolones [official government reference]
Glycopeptides [official government reference]
Phenylbutazone in female dairy cattle 20 months of age or older [official government reference]