Guppy

Systematic position: The guppy (Poecilia reticulata) belongs to the order Cyprinodontiformes and the family Poeciliidae. Despite its popularity in the aquarium hobby, when introduced into open water bodies and irrigation systems, it behaves as an aggressive invasive species capable of disrupting the biological balance in agroecosystems.

Affected crops: This species is not a direct consumer of terrestrial plants; however, it poses a significant threat to hydroponic systems, aquaponics, and rice paddies. In tropical and subtropical regions, guppies compete for resources with indigenous fauna, which naturally suppress the development of diseases and pests in agricultural crops.

Biology and life cycle: The guppy is a live-bearing fish with an extremely high reproductive potential. Females are capable of producing offspring every 30–40 days, allowing the population to adapt rapidly to new environments. The invasiveness of the species is reinforced by high tolerance to salinity levels, oxygen quality, and various temperature ranges, giving them an advantage in agricultural water reservoirs.

Nature of damage and harmfulness: The primary harm lies in the displacement of beneficial organisms (such as dragonfly larvae or specific entomophages) that control the populations of rice pests and other hydrophytes. By consuming zooplankton, guppies contribute to phytoplankton blooms and eutrophication, leading to the degradation of water quality required for irrigating sensitive crops.

Control measures: Managing population density in agrotechnical systems requires a comprehensive approach. The main strategies include:

• Installation of physical filters at the entry points of irrigation channels to prevent the ingress of individuals.
• Regular draining of temporary reservoirs where uncontrolled fish reproduction may occur.
• Biological control through the introduction of local predatory fish species that regulate populations of invasive poeciliids.
• Monitoring of water chemical composition to identify zones favorable for mass reproduction of the population.