We have 5 species of these, all endemic to Tasmania. They are ancient beasts,that haven't developed the familiar fused carapace of most of the shrimpy crustaceans. They seem to mainly sit on the bottom, but the one we saw swimming (below) flipped upside down and seemed to propel itself along the surface tension area of the water. Video should be the next upload. It's hard to see on this size, but I loved the fringe of fine long hairs bordering the final tail filaments.