bullying

Hey guys I have two gold severum & two juvenile oscar in my tank but recently one of my male severum bullying other fish . This severum always try to push my other severum behind the river rock in my tank and dint let her out (actually i dont know its male or female) like he try her not to...

Ive read online why my 10 inch senegal is nipping my 5-6 inch delhzi's fin. Ive kept senegal alone in a 60 gal tank, and everytime i introduce the smaller delhzi(numerous attempts) the next morning the fins are ripped to shreds and bleeding, soo i scoop it out and put it back to the old tank, i...