i had a platy that was very territorial against other platys..male female it did not matter... the platys that came with it never grew and eventually died because she would nip and chase them if they ate anything..even if it ate the scraps laying in the plants and rockss...
we named her phsyco fish...
she used to swim around with a big full belly like she was going to bust..
i bought a new school and she started again..i had to move her to her own little 5 gallon tank untill we got rid of her.. strangly enough she never acted this way with the other species ..
off the subject slightly,i've seen this behavior with angels they are subject to nip at other angels until they die .. the less dominant one will start swimming crazy and upside down (i assume from having it's *** kicked all night) )and the attacks get worse they will nip at them and drag them around until they are dead ..it was to late to save this one and i did not allow this and tried to save it..
finally when the male paired off with one it liked it eventually killed his mate. a female after 2 years of mating and breeding with no luck..
strange kinda like fish divorce or a domestic dispute!
of course this is an angel tank that i had years and years ago when i was much younger and did not have help from anyone like i get from here!!
even though he would nip at other fish but he would not try to kill them like he did angels???..
but likewise i would like to know why fish act this way towards they're own especially fish that are supposed to be peaceful like platys..