The objective of this study was to evaluate the effect of different diets for sexual segregation and growth of mature couples of clownfish. Three commercial diets and one experimental diet (in triplicate) were used: OTH (Otohime ® ); ALC (Alcon ® ); NRD (INVE-NRD ® ) and; ED (experimental diet). For sexual segregation, the larger individual was considered as female and the smaller as male. Following the experiment, the biometric parameters of the formed couples were evaluated. The duration of sexual segregation was significantly longer in clown fish fed the NRD diet compared to the OTH and ALC diets (p < 0.05). The different diets did not significantly influence the biometric parameters for either mature females or males. It is concluded that the duration of sexual segregation was influenced by diet.