21 Hashem created the great sea monsters, and all the living creatures of every kind that creep, which the waters brought forth in swarms, and all the winged birds of every kind. And Hashem saw that this was good.
כא וַיִּבְרָא אֱלֹהִים אֶת־הַתַּנִּינִם הַגְּדֹלִים וְאֵת כָּל־נֶפֶשׁ הַחַיָּה הָרֹמֶשֶׂת אֲשֶׁר שָׁרְצוּ הַמַּיִם לְמִינֵהֶם וְאֵת כָּל־עוֹף כָּנָף לְמִינֵהוּ וַיַּרְא אֱלֹהִים כִּי־טוֹב׃
1:21 The great sea monsters, and all the living creatures of every kind that creep, which the waters brought forth in swarms
Fish are highly symbolic creatures in Judaism. On Rosh Hashanah, the Jewish New Year, it is customary to eat the head of the fish in the hopes that the Jewish people should be as a head and not as a tail. Additionally, fish lack eyelids and so their eyes are never closed. This fascinating phenomenon serves as a reminder that metaphorically God’s eyes never close and that his gaze is never averted from His children. Fish also serve as symbol of fertility and continuity of the children of Israel. In Genesis 48:16 Jacob blesses his grandson Efraim in the name of his fathers Abraham and Isaac. Jacob’s blessing to Efraim is that his descendents should “grow into teeming multitudes upon the earth.” The Hebrew word in that verse which is translated as ‘grow’ is v’yidgu (וידגו) which is derived from the root word dag (דג) which means fish. Just as fish have the capability to birth many young at once, so too does Jacob bless his grandson with fertility and perpetuity.