The three common blennies of Plymouth are the Shanny, Blennius pholis, the Gattorugine Blenny, Blennius gattorugine, and the Butterfly Blenny, Blennius ocellaris. These have their habitat from just below high-water mark downwards. Thus, B. pholis inhabits the rocky pools from near high-water mark to the regions left dry by the tides; B. gattorugine is also to be found between tide-marks, but not so high up as B. pholis, and is more frequent in those parts uncovered by the spring tides; whereas B. ocellaris inhabits the deeper water and is always covered by the tide; it is frequently to be found on the dredging grounds in the region of the Mewstone and beyond the Breakwater.