Growth and body composition of Midas (Amphilophus citrinellus) and Nile tilapia (Oreochromis niloticus) reared in duoculture

Cichlids are of economical importance either as food (Nile tilapia) or as ornamental fish (Midas) and both exhibit territorialism and aggressive feeding behavior depending on availability of food and space. The objective of this study is to evaluate the growth rates and behavioral changes of Nile tilapia and Midas kept in mono or polyculture. Midas and tilapia were maintained in a semi-closed rearing system. Initial weight was 0.83 and 0.81 g for Nile tilapia and Midas, respectively. Four treatments with different fish proportions were used. Midas modified their feeding behavior and their weight gain increased in the 2:1 group. The 0:1 group exhibited the lowest growth rate throughout the experiment. Midas did not affect Tilapia growth across treatments. Interspecies aggressiveness was less evident when reared in monoculture. Intra and interspecies attacks were higher in the 1:1 and 2:1 groups. Proximate body composition indicated higher lipid levels in Midas across treatments in comparison to tilapia.