surveillance-camera-fish-robot-submarine-hi-res-wireframe-screenshot
looks like you included very many unnecessary tris at the main body (but I guess that was just for rendering?)
It looks pretty clean
Will you animate/texture it?
Looks pretty nice, but the engine cone at the back troubles me a little, it's unusual looking. Do water things use engines that look like that? Perhaps add some other jets to the sides so it can quickly turn and manoeuvre?
[DM]'s clan pic so far (poses only, bar needs A LOT of work)
Bonus: Bigger Version of my Avvy