The answer
This was done in boundless wisdom for the benefit of humanity. The aquatic world praises God and glorifies Him: “Praise the Lord from the earth, you great sea creatures and all the depths” (Ps. 148:7). Further, St. Basil rejects the interpretation of the waters above the firmament as being the spiritual powers of good, and those in the depths of the seas as the powers of evil.440
Fr. Tadros Yacoub Malaty
Notes
440 St. Basil of Caesarea, Hexamaeron 3.9 (NPNF II/8:70–71).