Laughing darter

I think it's a common darter and I know I shouldn't anthropomorphise, but "laugh" came to mind. Best seen Big!

Fred and I had a marvellous time in Kent with Aunty Vicky. The sun shone, and we enjoyed a long walk through fields of cut wheat and shimmering green woodlands to rest on a bench, taking in lovely views over the Medway. Fred ate his weight in brambles. On the houseboat, we scoffed a delicious lunch and played Scrabble. What a perfect day.