Fish are our first group of animals, but before we discuss them, a note on English. One fish is, of course, a fish. The plural is also fish. However, the plural of different kinds of fish is “fishes.” So if you catch five of them, you’ve caught five fish. If you’re talking about groups, as we will, its fishes.A Life of Life preps us to dive into discussing vertebrates. (Pun intentional)