I guess I should add to this with an explanation?

-Hair slows you down underwater, so it isn't really beneficial.

-What kind of animals live in very deep waters? Little, made mostly of water alien ones and large mammals due to the water pressure. So yeah, they're big.

-Fins are obviously needed. I decided to keep the arms because I felt it kind of lost the human part without them.

-Sharp teeth explain themselves.

-I did the glowing eyes to resemble what the anglerfish does in some way, using light to attract its prey.

So... Yeah. Enjoy.

C ya!