Link : http://www.funpoint.com/3dfishtank
Thanks to all the community for all the help.
I’ve codes… if you want some contact me in PM and I will give you one. Please do a nice review (should I say that?)
Dunno about spreading a video that shows how something is done… that just seems… wrong 
Also, caustic fx usually aren’t on water, they’re projected onto other surfaces as the result of light being magnified and/or reflected from the refraction of the water surface 