Definitely taking shape.I would like to see some lighting changes tho. Maybe some aquatic colored highlights in the back or near the surface Also the fish textures need some spark. I think iridescense or a sim effect and the eyes and under belly should be more lively with more detail. The fish doesn't look as alive...as it should.I realize this is a WIP so these are just observations. Looks good tho.

No need to think outside the box....
    Just make it invisible.