Yeah my female RD rules the tank always chasing my jag to the corner of the tank. Don't know if its breeding behavior shes digging a put n they occasionally lip lock
when mine was young hes use to nip my long fined oscar one day i came home and it looked like the oscar had enogh and swallowed him and spit him back up.that seemed to put a stop to it .trust me all he need is a REAL as* whooping
Midas/RD's are mostly rather insane, and will not give up once they have got an idea into their heads. There are not many fish which can outmuscle/bluff a midas/RD of a similar size once it's got it's aggressive head on.