Midas cichlids (Amphilophus spp.), hybrid ornamental fishes known for their name Flowerhorn and vibrant gold coloration, are highly prized in the aquarium trade. However, when introduced into natural ecosystems, they exhibit traits promoting ecological dominance, including aggressive territorial behavior, monopolization of shelters and feeding grounds, and high reproductive potential. In Lake Sampaloc, an inactive volcanic maar in San Pablo City, Laguna, Philippines, these cichlids have altered native fish assemblages, with small-bodied and endemic species experiencing notable population declines. The lake spans approximately 104 hectares with a maximum depth of 27 meters and retains water for up to 4 years, creating a stable but vulnerable ecosystem prone to invasive species establishment.
Field observations revealed that Midas cichlids are abundant throughout shallow vegetated areas and are actively farmed in a fish pen in Barangay IV-A. Fish farm caretakers reported that these fishes are as resilient as tilapia, coexisting alongside a fellow invader, the Jaguar cichlid (Parachromis managuensis), thriving even under pollution and eutrophication, and are sold primarily for ornamental purposes. Notably, visiting Laguna locals casually catch Midas cichlids during recreational fishing and incorporate them into their dishes, describing the fish as fattier and oilier than tilapia, highlighting a unique intersection of ecological impact and local culinary use.
The phenotypic plasticity of Midas cichlids enables survival under environmental stressors, including pollution, microplastic contamination, and hydrological disturbances. Shoreline pollution and open dumpsites further exacerbate ecosystem stress, reducing the survivability of native species while Midas cichlids continue to proliferate.
Addressing this invasive species challenge while supporting livelihoods can be achieved through targeted community-level harvesting, transforming captured fish into fishmeal for sustainable aquaculture. Integrating these efforts with responsible cage culture, wildlife-proof pen designs, community education, and participatory monitoring empowers local fisherfolk to track invasive species, observe ecological changes, and support policy enforcement. Combining traditional ecological knowledge with structured management and incentivized harvesting can simultaneously mitigate invasive species impacts, strengthen ecosystem resilience, promote biodiversity protection, and create alternative livelihood opportunities for communities around Lake Sampaloc.