There are times when semi-aquatic is only half the story. At the weekend we visited the Grant Museum of Zoology in London, part of University College London. The museum was used as a reference for students, and pulls no punches. They have a lot of pretty gruesome stuff in there, including a whole jarful of pickled moles, as well as the more uplifting sight of dodo bones and a near-complete quagga skeleton (brought up to totality by 3D scanning and printing reflected parts from one side to use on the other.) A combination of unsettling and fascinating. Anyway, a puffer fish in a cabinet caught my attention, and by the time I got home it had trans-hippogrified out of my sketch-book.
And a hippo swimming.