And if they can't pay for their own weight, that eventually means death. Tax collecting is a second profession. Home decorating is a third profession. Many itzu will live somewhere, and that somewhere will beg to be decorated. That decoration will be entirely a subject of fashion.
Fishing is fourth profession, and it means wandering empty space and gathering matter.
I imagine fishers would look like a fishing reel, just a spinner and one very long tongue. They'd be bigger than normal itzu and as black as solar cells. Fishers don't pay matter taxes, they are a city unto themselves. But fishers must protect themselves from being gathered by other fishers. Movers are a fifth profession.