I only have two cichlids in my 125 gallon tank, they are roughly the same size and I believe them to be male and female. I've had them for about three years now and aside from occasionally chasing each other they don't bother one another but today the male has been keep the female in a slight hole in the gravel on the bottom of the tank. He swims away and as soon as she moves he'll swim back over and slap her back down, with either his whole body or just his tail. This has been going on for about three hours now. This is the first time I've noticed this behavior and I'm not sure what to make of it. Any advice would be appreciated. Thank you.