It seems to be color 68. And it seems to be color 171. color 68 is suitable to paint a little part, because it is deeper water and bigger. color 17 is lighter, suitable for drawing Squidward running in the sunshine.

The darker color is good for painting Squidward in a dark place. Or paint the shadow part of Squidward's body. The character of Squidward is particularly funny. I quite like the character of Squidward.