the fish are bagged in the mornings and get put back into the tanks at night, i've seen them do it...they also do it for plants too
i think they are better off in the bag, you should see how many fish they can fit into a small tank
you can buy all types of fish pre-bagged, arowana, royal knife,discus,giant gouramis,red tail catfish...etc
i remember seeing 100neons for $18hk which is about $3.60nz all bagged ready to go