Major appetite regulators known for seven of the most studied representative fish families (serrasalmidae, cyprinidae, gadidae, labridae, pleuronectidae, salmonidae, and ictaluridae). Factors in blue (far left) and in red (far right) under the fish diagrams represent putative orexigenic and anorexigenic factors, respectively. Factors in green (middle) represent factors with no established effect on feeding. A “?” indicates uncertainty with regards to the role of a given factor in regulating feeding.