The fish motion essentially reflects the current state of water quality

so it is necessary to study the methods of obtaining the real-time dynamic motion characters of fish body in the field of biological water monitoring. Based on the analysis of fish locomotion model

the paper presents a fish activity model using the frequency of tail swing

which acquires some kinematical parameters

i.e.

tail frequency

swimming velocity

acceleration and so on. The results show that the model

which can be used as the theoretical basis of the application

represents the fish motion activity accurately and efficiently in the biological water monitoring.