The present Regulation sets forth general methods of diagnostics of intoxication of fishes by the main groups of toxic substances in accordance with special methods of diagnostics and chemical analysis of determination of single toxicants. Manifestation of intoxication of fishes happens in case of combination of the following factors: 1. presence of the source of pollution and toxic components in sewage; 2. presence of their determined concentration (dose) and duration of impact; 3. accompanying