"F*** me! What a large starfish!"
Chu Xian discovered that he could detect so much more at the bottom of the sea than he could while he was on the ship, both with his sonar and his mind's eye.
While using sonar from the deck, he could only see very general outlines of things, and the speed of the fishing ship was very fast as well, so he had a hard time focusing on the creatures on the seabed.
But while swimming around in his fish form, he could clearly see each individual fish or crab or starfish or coral.
And Chu Xian was focusing on all these seabed creatures because he suspected that the more precious finds would be on the seafloor. What if he found something like the red corals again?!
With that thought, Chu Xian kept observing his surroundings as he swam along and left the fish school lookout to Old Mu with the ship's equipment so that he could focus on his treasure hunt.