Shanny

Also known as the smooth or common blenny, Lipophrys pholis stands out from many other blennies with its absence of head tentacles. Long and slender, it has a notched single dorsal fin, with a spot between the first and second rays.

At high tide, L. pholis forages for a variety of foods, including barnacles, shrimps and seaweed. Once the tide recedes, you'll find this species in rockpools, often under seaweed or rocks. It can even survive out of the water (in a damp place) for some time, keeping water in its gill cavities ensuring a supply of the oxygen it needs.

In breeding season (April-August) the males of L.pholis will turn almost black with white lips, and once the eggs are laid by the female, the male will guard them for over a month.

Source 1: https://www.marlin.ac.uk/species/detail/1818
Source 2: https://www.wildlifetrusts.org/wildlife-explorer/marine/fish-sharks-skates-and-rays/shanny
Source 3: https://www.theseashore.org.uk/theseashore/speciespages/Additional%20Species/Blennyshanny.jpg.html