Answer:
U / U / U / U /
When fi- shes flew and fo- rests walked
Explanation:
The line above is an example of a iamb, iambic tetrameter, to be precise. Iamb means that the line consists of a sequence of unstressed and stressed syllables. The first syllable in an iamb is always unstressed (U). The one that follows it is always stressed (/). Tetrameter means that there are 8 syllables in a line (tetra means four, and meter consists of 2 syllables, so 4 " 2 = 8).
