A piscicide is a chemical substance

Chemical substance

In chemistry, a chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical separation methods, i.e. without breaking chemical bonds. They can be solids, liquids or gases.Chemical substances are...

 which is poison

Poison

In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....

ous to fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

. The primary use for piscicides is to eliminate a dominant species of fish in a body of water, as the first step in attempting to populate the body of water with a different fish. They are also used to combat parasitic and invasive species

Invasive species

"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

 of fish.

Examples of piscicides include rotenone

Rotenone

Rotenone is an odorless chemical that is used as a broad-spectrum insecticide, piscicide, and pesticide. It occurs naturally in the roots and stems of several plants such as the jicama vine plant...

 , saponin

Saponin

Saponins are a class of chemical compounds, one of many secondary metabolites found in natural sources, with saponins found in particular abundance in various plant species...

s, TFN

TFM (piscicide)

TFM is a common piscicide, i.e., a fish poison used to combat parasitic and invasive species of fish.The substance was discovered in 1958 when researching means to combat sea lampreys and it remains the primary lampricide in the Great Lakes area.TFM is nontoxic to humans and other mammals...

 (3-trifluoromethyl

Trifluoromethyl

Trifluoromethyl is a functional group in organofluorines that has the formula -CF3. The naming of is group is derived from the methyl group , by replacing each hydrogen atom by a fluorine atom. The trifluomethyl group has a significant electronegativity that is often described as being...

-4-nitrophenol), niclosamide

Niclosamide

Niclosamide is a teniacide in the anthelmintic family especially effective against cestodes that infect humans...

, Bayluscide (a proprietary name for the ethanolamine

Ethanolamine

Ethanolamine, also called 2-aminoethanol or monoethanolamine , is an organic chemical compound that is both a primary amine and a primary alcohol . Like other amines, monoethanolamine acts as a weak base...

 salt of niclosamide), and Fintrol.

Plant-based piscicides

Historically, fishing techniques of indigenous people around the world have frequently included the use of plant-based piscicides. Many of these plants are natural sources of rotenone and saponins.

The Tephrosia

Tephrosia

Tephrosia is a genus of flowering plants in the pea family, Fabaceae. The generic name is derived from the Greek word τεφρος , meaning "ash-colored," referring to the greyish tint given to the leaves by their dense trichomes.-Uses:...

, Wikstroemia

Wikstroemia

Wikstroemia is a genus of 55-70 species of flowering shrubs and small trees in the mezereon family, Thymelaeaceae.-Medicinal uses:Wikstroemia indica is one of the 50 fundamental herbs used in traditional Chinese medicine.-Species:...

, and Barringtonia

Barringtonia

Barringtonia is a genus of flowering plants in the family Lecythidaceae. A common name is cornbeefwood.Bengali name is "Hijalna".Species include:* Barringtonia acutangula* Barringtonia asiatica* Barringtonia calyptrata...

 genuses are well-known as fish poisons.