Even though Yan Fei knew that without his "help", the Kronosaurus would not have survived anyway, he still had mixed feelings.
It's not that he felt guilty, but more because he had worked hard all day, hoping to reunite the Kronosaurus family, only to fail in the end - despite his initial good intentions. Who knew that creature would have such a hard fate?
After transforming into the Kronosaurus and swimming in the pond for a while, Yan Fei changed again into a kind of light green fish found in the lake, then into a fish that looked down on everyone - these were forms he had acquired while in the lake. Although they might not be particularly useful, they could at least help him to get used to the real body of a fish.
After 'looking down' at everything in the pond for a while, he worried about the return of the Kronosaurus family, so he resumed his original form. Then, dragging the deceased Kronosaurus, he sunk into the deep lake.
