fishroom Share definition Flag A mushroom has gills on the underside of the cap like a fish. Hence it is called a fishroom. “the fungi is a mushroom & it has gills. So that means gills + mushroom = fishroom!!” fishroom by ThisIsTooFishyForMe September 18, 2022 0 0 Get merch Get the fishroom mug. Buy Now — $32.95 See more merch