Question: how to identify male and female in black ghost fish

title: Black ghost knifefish
text: Each species has a characteristic EOD baseline frequency range , which varies with sex and age within the species , as well . The baseline frequency is maintained to be almost constant at stable temperature , but will usually be changed due to the presence of others of the same species . Such changes in frequency relevant to social interaction are called frequency modulations ( FMs ) . The role these FMs have in communication is significant , as black ghost knifefish have developed jamming avoidance responses , which are behavioral responses that avoid the overlapping of EOD frequencies between conspecific individuals to prevent sensory confusion . Moreover , a study was conducted that focused on sexual dimorphism in electrocommunication signals . Female black ghost knifefish generate EODs at a higher frequency than the males , an FM which can be used for gender recognition . A study found the subdominant black ghost knifefish exhibited noticeable gradual frequency rises ( GFRs ) in their EODs whereas the dominant fish did not , supporting the researchers ' hypothesis that GFRs during communication are indicative of submissive signals . 

Answer: answer: Each species has a characteristic EOD baseline frequency range , which varies with sex and age.  Female black ghost knifefish generate EODs at a higher frequency than the males.