Laccotrephes tristis is a species of water bug commonly found in freshwater habitats. It is characterized by its elongated body, ranging from 1.5 to 2.5 centimeters in length, and its dark brown or black coloration. L. tristis is a highly efficient predator, using its long, slender legs to capture and feed on small aquatic organisms. Its ability to move swiftly and its voracious appetite make it an important component of aquatic ecosystems.