What is current best method for object tracking in real time?

I am trying to count fish as they swim in a river. Currently each fish image is counted multiple times as it moves through the region of interest. What is the best tool to use track a unique target (a fish) as it moves through the frame? It appears that MultiTracker may be obsolete. What is my best option? TrackerKCF? YOLOv8? Please advise. Thanks in advance.