I have a seashell wedding cake coming up in May. What molds are you using for the coral and starfish?
You can buy a starfish mold from www.jenniferdontz.com . Coral you can do free form by dipping them into white round sprinkles. It gives a realistic look to them! You can also use silicone putty and make your own molds using silicone putty from make your own molds.com. I bought a bag of seashells from Walmart and picked out what I wanted and made a bunch of them. Worked awesome! Especially for snail shells!
I'm working on one for a friend and I'm using white chocolate with candy molds for the shells and starfish then painting them with luster dust. Not doing coral so can't help you there. (Actually going to do some experimenting this afternoon. HTH
I did a sea shell cake and cupcakes. (in my pics) I used white chocolate and hand painted them with luster and petal dusts. I used molds I purchased and ones I made. I made fan coral by using an image and covering it with waxed paper and tracing the lines with melted chocolate.
You can use poured sugar over ice for a neat coral effect as well. There is also a coral mold.
the cheap chocolate molds works great for any of this.
Thanks for all the wonderful suggestions!