At kaitenzushi restaurants, plates of delicious sushi pass by customers on a conveyor belt. It is a very fun experience–especially for kids (and adults young at heart)–to grab your desired sushi from the conveyor belt and enjoy it straight away. Of course, a high-level monitor system ensures that no-longer-fresh sushi are promptly taken off the belt for appropriate quality control. However, even just one circulation around the restaurant can take minutes, which means the sushi you grab is probably not as fresh as it could be.
So, my advice to you is to order using the tablet on your table or communicate with the sushi chef directly. This ensures that everything is made fresh to order.
Also a pro tip would be to ask one of the sushi chefs which seafood ingredient is the freshest that day. Whatever’s in season is usually top-notch tasty, and the sushi chefs know best.