First step is to take the resolution up to at least 120, then on a new, long canvas (10 x 25) all 4 source photos are inserted to be blended together.
step 8 of 13
Here a closeup of the two top sources shows how shades of water are changed with hue/saturation tool until blues are close enough to start blending.They will then be merged and blended using the clone tool and soft brush.
step 9 of 13
Here the blending has been completed.
step 10 of 13
Now the bottom source photos are merged so that they can also be blended together, then the top and bottom sections will be merged also and blended.
step 11 of 13
With merging of sources completed, Some anemone-like shapes are added at bottom left using the smudge tool, then Large fish is chopped and added.
step 12 of 13
Smaller duplicates of the large fish are added after scaling them and cutting down the contrast for them as they go into the distance.
step 13 of 13
Finally, layers are merged. I created a pattern layer from the water which was in the source photo of the Batfish, and put that over the entire picture then cut it to under 10%. A brown filter was also placed over the entire picture and cut to under 10%. a few bubbles were created coming from the close-up fish. In source there were actually no bubbles coming from fish at all, but I used the dodge tool to indicate just a few.