just bought a trio of pepermint. 2 gravid female. only 2 days later. found 1 dead female. look like been fighting but not sure. can some one tell me if fishes fight to dead? or could be other reason. they were strong wen brought home. was kept together wid 2 angel. and 1 male albino and 1 female bristlenose. the anal part where she will lay egg look very wide opened