I found an awesome pot from Unurth that looked like the ocean to me. I decided to fill it with these under the sea plants. The pot wasn't big enough to use them all, but I was able to fit in some of my favorites.
If you end up working with any Euphorbias, remember the white sap is poisonous and can irritate your skin. I finished off the arrangement with the Gold Tan Top Dressing from Bonsai Jack. The color reminded me of sand on the ocean floor but it had more texture.
When you're working with a pot that has an obvious front, like this one I used (the “bubbles” you see on the side should really be in the front), make sure you remember to look at that when you're placing the plants!
Something I want to do with my next under the sea creation is add in some sea shells or even little fish! You may have noticed I didn't use all of the plants I got, so I'm definitely planning another arrangement.
Also, keep an eye out for arrangements you see that have that “under the sea” look to them. While I was at Waterwise Botanicals, I noticed that several of the arrangements they had for sale definitely looked like something you'd see while snorkeling or scuba diving.