  The unified dark fluid model unifies dark matter and dark energy into a
single component, providing an alternative and more concise framework for
interpreting cosmological observations. We introduce a PAge-like Unified Dark
Fluid (PUDF) model based on the PAge approximation (Huang 2020), which is
parameterized by the age of the universe and an $\eta$ parameter indicating the
deviation from Einstein-De Sitter Universe. The PUDF model shares many similar
features of the standard Lambda cold dark matter ($\Lambda$CDM) model and can
effectively describe the large-scale structure formation and late-time cosmic
acceleration. We constrain the PUDF model with the Planck 2018 cosmic microwave
background anisotropies, baryon acoustic oscillation measurements including
those from the most recent DESI 2024, the Pantheon+ sample of Type Ia
supernovae, and the Cosmic Chronometers compilation. Although the PUDF performs
well in fitting all the cosmological datasets, the joint analysis of the data
still favors the $\Lambda$CDM model over the PUDF model, according to the
Bayesian evidence of model comparison.
