From the Greek ichthys — fish and Latin caedo — kill.

Ichthyocides are chemicals used to destroy undesirable (weedy) fish species from an economic point of view.

Chemical agents for the destruction of undesirable ("weed") fish species in order to increase the fish productivity of reservoirs by growing valuable fish species. Ichthyocides used in world fisheries practice, by their nature, belong to inorganic, organic and organoelement substances. 

Inorganic Ichthyocides — copper sulfate, calcium hypochlorite, sodium sulfite, sodium cyanide, ammonia water, as well as hydrates of sodium and calcium oxides are used both for the selective destruction of eggs, larvae, juveniles and adult fish, and as a total action ichthyocide. 

Organic ichthyocides are natural organic substances extracted from various plant raw materials, some antibiotics — antimycin A1, A2, and A3, levoristatin and synthetic organic preparations of poly-, di- and monohalogen derivatives of carbocyclic compounds, as well as a number of other agents belonging to various classes of organic substances (polychlorocamphene, aldrin, dieldrin, etc.). 

Organoelement compounds are represented by organic phosphorus compounds (malathion, malooxone, gution, derivatives of chlorvinyl phosphates). Ichthyocides are toxic to humans and animals, and precautions must be taken when working with them.