Part 1 Ecological fundamentals: aquatic ecosystems - ecological approach, ecological zoning, typology, fluvial hydrosystem, limnological aspects of lakes; nature and dynamics of the components of a medium - terrestrial environment, water movements, water biotic components; fish - morphology, anatomy, classification, elements of physiology, biology, and ethology; investigations in the medium -general arrangements, elementary investigations, marking, sampling, detection, fish productivity, hydroecological study. Part 2 Fish breeding: improvement of natural spawning conditions - access to spawning areas, protection of spawning areas, improvements in spawning areas, artificial spawning beds; in situ hatcheries - incubation boxes, incubator cradles; growth in a natural medium - hardiness of species, breeding mediums, improved extensive breeding; induced breeding - cyprinids, percomorphs, esociculture, salmonids; intensive fish culture - artificial reproduction of the trout, reproductive salmon, fertilization and incubation, hatching and rearing of fry, raising of summerlings, growth and mortality, introduction of salmon in the natural medium; breeding of the fishes - raising the catfish European eels, raising the sturgeon, raising the eel, tropical fish culture; health problems - investigation of causes, therapy, prevention; suitability of mediums - classification, situation, development; adverse effects - historical changes, adverse effects on the catchment area, adverse effects on the aquatic medium, pollution, estimation of water quality, organization for detection. Part 3 Management of aquatic mediums: physical management - maintenance of the aquatic mediums, classification of ponds, creation of artificial mediums, correction of water course, management of water course for migratory fishes; intervention in the biological medium - amelioration of fish culture mediums, artificial equilibrium, fish production; economy of aquatic resources - development and management strategies of fish stocks, animal resource, suitability of the aquatic medium, management of fishery resources. Part 4 Appendices: formulae and programs -on the knowledge of the aquatic medium, on the fish population, about water, harmful effects. Glossary; references.