This study developed an IBM (individual-based model) to model fish movement trajectories integrating hydraulic stimulus variables (turbulent kinetic energy (TKE), velocity (V) and strain rate (SR)) to which fish responded, and the rules for individual fish movement. The fish movement trajectories of the target fish, silver carp (Hypophthalmichthys molitrix), were applied to model fish trajectories in a 1% vertical slot fishway at a discharge of 13.5 L/s. Agreement between measured and simulated trajectories implied the plausibility of the movement rules, which illustrated that the fish movement trajectories model has the preliminary ability to track individual fish trajectories for this fishway.2 of 16 etc.). However, these models do not incorporate individual fish movement behavior with hydraulic parameters. The main challenge in modeling fish movement is linking these parameters. The hydraulic information of the fishway is regarded as a stimulus, which is the Eulerian framework, while the response of a fish to a stimulus is an individual-based framework, which can add individuals' behavior and track their movement. One advantage of the individual-based framework is its relevance to internal states, such as environmental conditions or individual heterogeneity [17][18][19][20]. Therefore, an individual-based model (IBM) approach can be applied to model fish movement trajectories in the fishway. Goodwin et al. (2006) [21] developed a model called ELAM (Eulerian-Lagrangian-agent method) using an IBM approach to model fish movement paths at a hydropower dam forebay. Later, Gao et al. (2016) [12] established an Eulerian-Lagrange fish movement model of a fishway. However, the model only considered turbulent kinetic energy (TKE) as a hydraulic stimulus factor. Validation and calibration of a model principally depends on experimental data. Therefore, it is important to consider a more refined model.Before using the IBM approach, one theory was based on the assumption that the response of fish in the experimental fishway was the same [12]. That means the physiological indices were constant, even then the physiological indices may change after a response has been made. If so, the above assumption implied that a fish swam with similar/ average velocity in all the pools in the model.Black carp (Mylopharyngodon piceus), grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molitrix) and bighead carp (Hypophthalmichthys nobilis), herein called Asian carps, are the most commercially important freshwater fish species in China, especially in the Yangtze River basin. Asian carps are typical potamodromous fish and have typical migratory activities in spawning and nursery periods [8]. Most research has focused on the swimming performance of carps [8], and little is known about how the fish respond to hydraulic stimulus variables in fishways. The commonly used hydraulic parameters include flow velocity and turbulence [22,23]. It has been well recognized that the slots of fishways change the spatial distribution of th...