Question

how does anomalous behavior of water help aquatic life

Answer 1

Because of water's anomalous behavior, ice is less dense than water, and hence it floats. In winters, lakes tend to freeze. If this were any liquid other than water, the top layer would freeze and sink to the bottom, crushing aquatic life beneath it. But because ice floats, this doesn't happen, and it also saves the water below the top frozen layer from freezing as well.