Species details: Gobiusculus flavescens

I caught mine in a marina in Falmouth (Cornwall). They are surprisingly easy to catch, as you can easily approach them slowly with a net until you are within striking range and then scoop up a few at a time. The shoal reforms after a short while at nearly the same place, and you can get more. I only took four because my tank was well-stocked already.
They really are the perfect mid-water fish for a temperate marine setup. They are attractively patterned, small, stay together in a loose shoal and readily accept frozen foods. The pupils of their eyes are highly reflective, which gives them a slightly spooky appearance. Contrary to other gobies I've kept, they always remain in mid-water and only settle down on the substrate at night. They do not harass each other or any of the other tank inhabitants.