Yes, the one in this tank was very active. He's actually in the photo but you can't see him. There is a vague blur somewhere at the very top left, by that patch of light and squiggly branch, and that is the platypus, but he was moving much too fast to photograph him without using the flash (note that the flash wouldn't have bothered the platypus - they shut their eyes tight when underwater - but it would have just bounced off the glass and ruined the photo).
