Found this Acilius sulcatus in my pond. Since diving beetles are rare visitors in it compared to the countless backswimmers, dragonflies, and water striders I wanted to keep it inside at least for a few days to get a good look at it and try for better footage later. I put it in a large plastic tub with lots of floating plants and a log. Really fun how active and hungry it is. When I offered a piece of fish with tongs to it, it grabbed it without any hesitation.

Kinda makes me wanna start searching some local ponds for Dytiscus marginalis and properly keep those for a longer time.