ABSTRACT:
Social behavior is a common phenomenon among vertebrates, notably in fish, birds and mammals. It has been evolved within the species purposefully to support effective foraging, predation avoidance and fitness. Although all animals have predilection to live in a group, it is very intense in a few species. In many fish species it is an obligatory behavior, whereas in many other fish species it is opportunistic during group foraging and predator avoidance fish express their social behavior by enhancing the locomotor activity. The synchronization in locomotor activity reflects their social behavior based on interaction among members of the same species through sensory cues, like vision and oilfaction (pheromones); and also is based on phenotypic characters, such as body size, body color and gender. It has also been reported that day and night cycle affects their social behavior. Study of inter-individual interaction under laboratory conditions often helps to understand intricacies of social behavior. The factors, such as group and group size may influence circadian periodicity in fish under different environmental conditions. In summary, such studies come under the fold of interesting researches in the realm of fish biology.