I have a paid of lightening maroons that I’ve had for almost a year in the same tank. I bought one and about a month or lll later decided I wanted a mate for it. They have been fine together in tank this whole time with the occasional “punk” of the bigger one and the smaller one would quiver. Well a few days ago I noticed the bigger one was chasing the other one non stop and the smaller one was no longer submitting and just running and trying to hide. He was getting beat up pretty bad so finally I put him in an acclimation box for a few days. While he was in the box the female still tried to get to him. Tonight I let him out and she immediately started chasing him again to the point that I thought she was going to kill him. This time I put her in the box. Why all of a sudden would this happen and what should I do to get them to get along again?