It was a dog walk, not a naturalizing expedition, but the chance to explore rarely seen sandbanks and never before uncovered rocks was too much to resist. Plenty of new things to see, including this blenny, stranded under a rock by the receding tide:
Thinking it must be dead, I gave it a prod to better arrange it for a photo. To my surprise it flopped around, looking as indignant as a fish can. It had survived out of water in the moist atmosphere under the rock for at least an hour. I picked it up to put it in a nearby rockpool, but it wriggled from my hand, dropped to the rocky beach, stuck out a pair of long pelvic fins then half walked, half squirmed in a most missing-link-like way to the neaby rockpool and vanished happily into the sand. I think it's a common blenny, also called a shanny.