I have no idea what species of fish this is supposed to be so I colored it up (watercolor markers) like no fish I have ever seen! The carved stamp is just the black lines, and I did repeat stamping as I often do with a smaller stamp.
The swirling water is also colored with markers and I added rubon text at the top of the card.
I added Glossy Accents to the water and the fish eyes then applied Stickles to the fish. Here you get a better look at that effect.