Hi Linda - I had the same problem, some cabins didn't have a fish extender. If you like you can leave it behind the 'fish' on the wall by the door or chose to skip them. Its up to you.
If someone who is pretty proficient in powerpoint or excel (definitely not me - I'm hopeless) can map out some cabin numbers of those as we get closer to sailing date, that would be a great help. Also, if anyone is interested and has a fish extender, its that person's responsibility to hunt down the floor monitor and update the list. And if they upgrade to a different deck then they would need to make sure that they update both floor lists.
What works best is if someone volunteers who already has a confirmed room assignment or even if they don't once the room assignments come out, then someone just post here. Looks like several people won't be leaving until a few days out. For some of us, we'll be there ahead of time. So as for my gifts, they will come from the MED!