It really looks like Marilyn had a fantastic time making this amazing background to go with the Fish Group (895-27) stamp set! She did so well with the colors in the fish and the background they actually look like they are in the water.
She used the Nested Circle Die Cuts (5002D) to cut the background and the fish out. When she did this it makes it look like you are looking through a port hole on a boat or maybe looking into the aquarium, which makes it really fun.
For some more fun elements Marilyn used the Small Star Outline Die Cut (5100-06D) which she used the same background. Her little gem embellishments look like little bubbles as well.