decided to try an escher-style tessellation again after some discussion on the Origami mailing list. this is, obviously, a rather simple model, but something more complex would take more time than I have right now.
this model tessellates across the plane, although it requires two differently sized triangles to fill in some gaps. you can see the tiling pattern here.
I know they don’t really look all that much like fish (more like goldfish crackers, if you’re from the US) but it’s what came to mind. I came up with some more complex figures made up of larger groups of shapes; I’ll try to give some of those a go at a later point in time.
All my diagrams that exist are available online at: www.origamitessellations.com. I only have 4 documents up there currently, but there are more in the works. If I come up with some better fish tessellations I’ll make sure to diagram them!