Zebrafish muscle. Confocal light micrograph of the interior of an intact zebrafish (Danio rerio) larva, in optical section. The tissues have been stained with fluorescent dyes and illuminated with a laser. The long, green striated objects are individual muscle cells. A confocal microscope detects light only from the focal point of its objective lens. By moving the focal point, images of thin sections of an intact specimen can be obtained. Magnification: x200 at 6x6cm size.