Symbolism, Imagery, Allegory
Forget puppies and cats—the Minor Prophets were much bigger fans of swarming insects and fish. One of the things that made these critters so useful was that they were teeming with significance. The abundance of fish in the sea can be a symbol of life in abundance, similar to the way that figs and grapes express the fertility of land. Or, well, the way that God can undo the abundance of his creation.
Therefore the land mourns, and all who live in it languish; together with the wild animals and the birds of the air, even the fish of the sea are perishing. (NRSV Hosea 4:3)
A school of fish and a swarm of insects each illustrate the vulnerability and helplessness of a leaderless people:
You have made people like the fish of the sea, like crawling things that have no ruler. The enemy brings all of them up with a hook; he drags them out with his net […]. (NRSV Habakkuk 1:13-14)
Like one of the original ten plagues of Egypt, the swarms of locusts in the book of Joel are God’s destructive army. An agrarian economy could be done in by a serious locust swarm, so God brings out the locusts whenever he wants to describe a truly horrendous and complete catastrophe.
What the cutting locust left, the swarming locust has eaten. What the swarming locust left, the hopping locust has eaten, and what the hopping locust left, the destroying locust has eaten. (NRSV Joel 1:4)
Be dismayed, you farmers, wail, you vinedressers, over the wheat and the barley; for the crops of the field are ruined. The vine withers, the fig tree droops. Pomegranate, palm, and apple-- all the trees of the field are dried up; surely, joy withers away among the people. (NRSV Joel 1:11-12)
Forward …. munch!