The TRIX index is an approach that can be used to determine the fertility status of a water body. This TRIX index uses the main and supporting approaches. The purpose of this study was to determine the fertility status of Lake Daek using the TRIX trophic index, where this research was conducted in July-September 2023 at Lake Daek. There are 3 stations in this study, namely station 1 is the inle…