Fig. 4: A burbot in a rock crevice at about 25m depth which observers the stranch bubble fish with light beams. In the foreground one can see a sweetwater polyp. — Nikon D200 Nikkor AF-S DX 12-24mm, Hugyfot housing, Herrliberg (small parking place, towards left), Lake Zurich, 13 June 2007 Nikon D200; Δt=1/125 s; f=60 mm; f/16.0; ISO 200; 13 June 2006 19:10:24