Interspecific Ecological Interactions of Invasive Janitor Fish (Hypostomus duodecimalis) and Kanduli (Arius manillensis)

This study investigated the ecological interactions happened between the Janitor fish, an invasive fish, and the Kanduli, a local fish in the Philippines. The Janitor fish (Hypostomus duodecimalis) from South America is an invasive fish species that is spreading in local waterways and forests, threatening to edge out the country's indigenous plants and animals (Berame and Alfonso, 2019). It was originally introduced locally for aquariums, but careless handling and weak controls allowed it to escape into the wild.

These foreign species may look like cute fishes but government wildlife experts warn that they are displacing native fish while causing massive harm to the fishing industries (Macaraig, 2011). This study focused on predation and interspecific competition, as well as the growth rate and survival rate of the Kanduli that were made to interact with the Janitor fish. Data collection was conducted in one of the researcher's houses in Dagupan City during the second semester of 2022-2023 school year.