The aquarium itself

In[5]:=
  l = 4;
  w = 1;
  h = 2;
  aquarium =
    Graphics3D[
      {Line[{{0,0,0},{w,0,0},{w,0,h},{0,0,h},{0,0,0},
             {0,l,0},{w,l,0},{w,l,h},{0,l,h},{0,l,0}}],
       Line[{{0,0,h},{0,l,h}}],
       Line[{{w,0,0},{w,l,0}}],
       Line[{{w,0,h},{w,l,h}}]}
    ];

In[6]:=

  Show[aquarium];

Up to Aquarium