In this (rather) short video I'm showing how you can create a simple project which you can let fish to swim on any geometric surfaces using Houdini.
[Project File] https://github.com/jhorikawa/HoudiniHowtos/tree/master/0043%20Fish%20on%20Surface
[Portal Page]
Facebook Page: https://www.facebook.com/ParametricProceduralHoudini/
[Books]
Algorithmic Design with Houdini: http://www.bnn.co.jp/books/9788/
Tiling Pattern with Houdini: https://gumroad.com/l/OVDgY
Books on BOOTH: https://orangejellies.booth.pm/
