4 colours, MS Paint standard black, two greys and white.
Although yes it looks good, I don't think there's really much to discuss.
From the title I thought it was some kind of fish. Not really much to criticize, the thickness is uneven but that gives it more personality.
Pretty jagged, and the AA is off in several places.
The only thing I think that needs fixing is that some areas are straight when they should be more curved.