Fluids is open-source software for engineers and technicians working in the fields of chemical, mechanical, or civil engineering. It includes modules for piping, fittings, pumps, tanks, compressible flow, open-channel flow, and more. The fluids library depends on the SciPy library to provide numerical constants, interpolation, integration, and numerical solving functionality. fluids runs on all operating systems which support Python, is quick to install, and is free of charge. fluids is designed to be easy to use while still providing powerful functionality. If you need to perform some fluid dynamics calculations, give fluids a try.