I recently had to make a seaside card for another challenge that I filled with shells but went an entirely different way with this one using the same stamp set from MFT called Sea Life.
I used Distress Oxide for the background adding some misting and a bubble stamp dipped in water. The fish and seaweed were colored with Distress Ink markers directly on the stamp and then misted. Again the "what sentiment do I use?" cropped up until I saw this one on the MFT Polynesian Paradise set and thought it was rather cute.
The Design Team has some wonderful sea inspired cards for you to see. Check them out and then make a card of your own. You may be our next Chic of the Week.