Take a look to this link, it's a Spanish shop of sculpted foam puppets, you will see several fishes.
http://www.latiendita.es/paginas/moviles.htm

How funny!!

Looks good Cristina! Are you going to give your shark some teeth?

I supose so,Shawn,but don't know how,I'm planning to do it as reaslistic as posible....

Do you have what is called craft or funky foam where you live? It looks like this. http://www.clarkcraft.co.uk/product_info.php?products_id=13261  It is an EVA or closed cell foam that comes in sheets like paper and is about 1/8 to 1/4 inch thick.  It works great for making teeth.

I do think this material in Spain is named as Goma Eva. Now I'm talking to you, I've seen in project puppet they're sending now blocks of foam, and I've noticed the price is much higher than here in Spain. A "sheet" of 1,5 metres and a wideness of 1.5cm had cost me 5€ more or less (hope you understand me! as I'm not using the translator).

So, how do you cut teeth from these sheets?

I understand you.  The foam I am talking about is not what Project Puppet sells but I searched for Goma Eva and it looks like it is what I was talking about.

You can cut individual teeth out of these and glue them into the mouth is you want or you can do what I did with my Mule mascot and cut a strip of foam and then cut the shapes of teeth in the one side of the strip. Hard to explain but perhaps this picture helps you to understand.

His teeth are more like a humans and squared off but for shark teeth you would gut them more like triangles.

I just use scissors to cut them out.

Does that help?

Of course you've helped me Shawn! How do you glue them?
thanks a lot

I hot glued these teeth in but you could use contact cement or even a foam and fabric glue like FabriTac. I like FabriTac but it takes longer to dry and I was in a hurry.  When I use a foam and fabric glue I normally use pins to hold what I am gluing in place while it dries.

P.S. Another name brand of glue that I like is Tacky glue. Again takes some time to dry but can be a cleaner look.  Tacky glue is a lot like a regular pva white glue that kids use only it is a lot thicker so it stays put where you want it instead of running.  Look in your local craft or hobby store since I bet the name brads are going to be different where you live.  Just look on the label to see if it works with fabric or foam.