There are various species of Trevally, ranging in size from 8kgs in weight (Golden Trevally), 10 kgs in weight (Silver Trevally) to a mighty 25kgs in weight (Giant Trevally). Trevally are fast-speed predatory fish, otherwise named Blurters, Jacks and Trevors, and are found in coral reef and coastal ecosystems across the Pacific and Indian oceans. They typically congregate in massive schools, sometimes exceeding 1500 individuals. Fish are able to synchronise their movements in a school by keeping in touch with one another via a highly sensitive lateral line which runs down the length of their bodies. They also recognise their own kind through sight and smell. Eighty percent of the known 20,000 fish species school at some stage of their life cycle. Fish school for two main reasons; to avoid predation, and to use the slipstream of their comrades to make travel less energy-taxing.