Asian isopods, high-humidity, slower breeding than the European genera, and the source of nearly every price spike this hobby has seen.
The rubber ducky is the case study. It entered the trade at a price that made isopods briefly look like an investment category, held for a couple of years on genuinely slow reproduction, then fell steadily as breeders figured out the husbandry. Same arc for several others since.
Two things to know. Reproduction really is slower here than in Armadillidium or Porcellio, so corrections take longer and prices stay high longer. And much of what sells as Cubaris is not Cubaris, with several popular forms belonging to Merulanella or other genera entirely. The trade names are doing all the work and they are not reliable.