Social interactions of swarm fishes can be at least partially mediated by olfaction, including imprinting on kin. Zebrafish, or Danio rerio, has in recent decades come to the forefront of genetic vertebrate model organisms and in particular for aquaculture fish species. The relevance of olfaction for particular fish species is not generally correlated to their systematic position, nor is there a general correlation to the size of the olfactory receptor repertoire. Bony, cartilaginous and jawless fishes all possess a well-developed sense of smell. Fishes, like all vertebrates, possess separate smell and taste systems as well as solitary chemosensory cells distributed over the skin surface. In the absence of sniffing, fishes have several solutions to increase the sensitivity of odor detection. Odorant responses in olfactory bulb of fishes generally form a coarse chemotopic map, such that chemically related odorants are represented in neighboring areas of the olfactory bulb. The olfactory signal transduction of ciliated and microvillous receptor neurons is distinctly different.