Mogget sarcastically responds with "Fine!" while expressing his discomfort about being wet, cold, and full of holes. This suggests he is having a rough day and is possibly frustrated with the situation he finds himself in.
The quote also hints at a sense of humor or resignation as Mogget comments on the challenges of their adventures, describing it as "another fun day on the river," despite the apparent hardships, highlighting the tone of the scene in the book Lirael by Garth Nix.