Surprise surprise, the fish disapproves. And surprise surprise, he voices his disapproval. He doesn't like the Things any more than he likes the Cat.
His main point, once again, is that guests shouldn't be over when their mother isn't home.
Valid point, fish.
The Cat lifts up the teapot (which will never be the same now that the fish has been in it) and meets the fish eye to eye. Rightly, our fish is looking extremely stern and angry. You know the look.
Once again, the cat won't take no for an answer. Check out how smooth he is: "They are tame. Oh so tame!/ They have come here to play. They will give you some fun/ On this wet, wet, wet day" (188,191).
We are sold.
But the fish isn't. Too bad—what can he do? He's just a fish in a pot.