if you take the fish to a place where they have a scanner you can have them scan them in the bag. better to have in separate bags. no need to release them or knock them out, as once in a bag the scanner can read them ok. if they read a number, you can sell without being worried about being an illegal seller. a fine point would be if the fish have been legally imported but probable that they were bred locally. as someone posted above the first four digits tell the farm location. i am not sure because i dont know where i saved the tag number explanation. from memory it wil show the farm id number/ location and the date of tagging. i havent studied it hard as it was not important at the time. i stumbled across it on the net and dont remember where i saw it.
i once had a scanner and a fish yet had someone else try the scan and it was not succesful but it was free swimming in a big tank and may not have yielded a result that way.