Hepatic/gut/brain leptin increases in expressions are seen post-prandially in goldfish (Tinoco et al., 2012, 2014b), common carp (Huising et al., 2006a) and zebrafish (Tian et al., 2015) (Cypriniformes) as well as pacu (Volkoff et al., 2017) (Characiforme). However, in rainbow trout plasma leptin levels decrease post-feeding (Johansson and Björnsson, 2015).