Can someone give me a tutorial to make a fish cake from the carving to the fondant and so on?
Thanks

Here's a tutorial from another CC member...it doesn't include everything you're asking about, but maybe it'll help: http://www.cakecentral.com/cake-decorating-ftopict-606308.html

You should also try picking up "Collette's Cakes: The Art of Cake Decorating", she has a detailed tutorial on how to do a fish cake. You could probably find her book at your local library.