Two of the most important factors affecting fish feeding are the size
the fish has already reached and the temperature of water the fish inhabits.
In general terms, food consumption increases first, peaks at an
optimal temperature, and then decreases as temperature continues to
rise (Brett and Groves, 1979). The same trend, independent of fish
size, was also observed for FC over the range of 23–35 °C in this study
(Table 2). The increased FC with temperature increase from 23 to
33 °C can be at least partly attributed to the increased energetic demands
of fish at higher temperature for growth, activity and maintenance
demands increase as ambient temperature increases not
beyond the upper thermal tolerance limit for the species. However,
at 35 °C the decrease in the appetite of fish was marked and from a
practical point of view, there was some risk of overfeeding in cobia
farming. For a certain temperature FCa increased but FCr decreased
with increased size, i.e. larger fish consumed more food than smaller
fish but had a contrary trend based on their unit weight, which indicated
that food cost for unit weight of smaller fish was higher than
that of larger fish.