"fuckyeahmolecularbiology:  Sensory axons (long, slender nerve fibres) covering the tail of a 3-day-old larval zebrafish. This is a ""Brainbow"" image made using confocal microscopy. In the Brainbow technique, cells randomly choose combinations of red, yellow, and cyan fluorescent proteins, so that they each glow a particular color. This provides a way to distinguish neighbouring cells of the nervous system and follow their individual pathways."