Fish parasites are ecologically important because they shape community and ecosystem structure by influencing trophic interactions, host fitness, and food webs. We surveyed fish parasitofauna from Lake Taal and provided initial quantitative and qualitative measures of parasite burden. This was then correlated with fish size, as a preliminary attempt to relate parasitism with fish overall fitness. A total of 60 specimens of Oreochromis niloticus, Glossogobius giuris and Clarias batrachus were collected from the lake in June, October and November 2010. From these, five taxa of digenetic trematodes (Opegaster sp., Erilepturus sp., Euclinostomum sp., Orientocreadium sp., and Clinostomum sp.) and one parasitic cyclopoid (Lernaea sp.) were collected and identified. Results revealed that the most prevalent parasites, in both occurrence and number, were Opegaster sp. in G. giuris and C. batrachus, and Lernaea sp. in O. niloticus. C. batrachus was the most burdened as it harbored parasites in most of its internal organs. Linear correlations reveal negative trends between parasite burden and fish size for all fish species analyzed, suggesting that smaller fish tend to harbor more parasites than larger fish. However, this relationship was not found to be statistically significant (p>0.05). Nevertheless, these results reveal the challenges that many researchers will face in their effort to understand the implications of parasitism to both caged and feral fish, in relation to natural and anthropogenic factors. Moreover, it highlights the need for more ecological studies on parasitism in the Philippines, if we are to improve fish conditions in both open waters and caged areas not only in Lake Taal, but also in all Philippine lakes, especially those that are being utilized for aquaculture.