Zebrafish eye. Scanning confocal light micrograph of tissue from the eye of a zebrafish, showing the lens (round, lower right). The image has been stained for cytoskeletal fibres (green). The staining and autofluorescence has also highlighted other proteins and DNA. This image includes the zonular fibres (bottom left) that connect the lens to the ciliary muscle. This image consists of about 20 optical sections as a collapsed stack. The zebrafish (Danio rerio) is a popular model organism in biological research. Magnification: x165 when printed at 10 centimetres across.