Pantabangan Lake, renowned for its pristine waters and diverse native fish species, faces a pressing challenge with the invasion of largemouth bass (Micropterus salmoides), locally known as Tawis. Introduced in 1907, largemouth bass now dominates the ecosystem, altering its dynamics. The largemouth bass, a carnivorous species known for hunting in groups, lacks natural predators in Pantabangan Lake. However, if it consumes the barbels of catfish, both species perish. Consequently, human anglers stand as the primary means of largemouth bass population control. With their prevalence in nine out of ten boats compared to blackchin tilapia’s presence in only four, largemouth bass exhibit greater aggression and widespread distribution throughout the lake. Catch weights typically peak at ¼ kilogram, with lengths ranging from 22.86 to 55.88 centimeters, indicating maturity. However, larger specimens above 50 centimeters are increasingly scarce. While the 30 surveyed respondents demonstrate awareness of largemouth bass presence and utilize them to some extent, further monitoring is essential to assess negative impacts on native fish populations. Management strategies should focus on mitigating ecological consequences, understanding environmental factors influencing largemouth bass behavior, growth, and distribution, and implementing measures to preserve Pantabangan Lake’s biodiversity.