msh+frozen+fish

The author uses frozen fish as a symbol to show that the students aren't interested in poetry. In his opinion the senior class "hates" poetry and he tries to get them excited for it. Saying "orderly as frozen fish" he is criticizing how structured their way they look at poetry is. The teacher wants them to be active, to "move around" in the poetry. That's basically what then happens, the students, all the sudden not being frozen anymore, start swimming around in the water together with their teacher. All this relates to school, because it is showing how poetry should be taught in a senior class and in school overall.