soap making essentials

I am assisting with making bridal shower center pieces. Another person has purchased decorative hand made fish soaps that will be used as prizes at its conclusion. I am looking for a way to make them appear as if they are floating and it is a fish tank. So far I have only come up with filling the bowl with clear stones. I looked at that special gel stuff in Michaels, but I need to be able to get the soaps out to give them away as gifts. Any ideas?

Maybe find something to use as a lid for the tank and use thin, clear fish wire to hang them from the lid. You wouldn’t have to fill the tank with anything.