Flag Acara Problem

Well, I recently have to swipe the power filter off my 29 for another tank, so I tossed in a mature sponge filter. One of my flags has fallen in love with it and is guarding it. He has the other two flags and the angel pressed against the other wall!

Now, I'm guessing that he wants it for a spawning spot, but I'm not sure if the other two flags are even female. They're still pretty small and the dorsal fins were nipped off when I got them (they were in a tank with cons at the store :headshake2.

Will removing the sponge filter effectively take away his territory or will he pick a different spot? I got these guys because they are suppose to be pretty peaceful.

BTW, he's all dressed up and beautiful. Lots of black and turquoise instead of blah tan.

The tank is a standard 29 gallon. It have sand substrate with river rocks. There are two big pieces of driftwood on either side, live plants (ludwigia, java fern, and moneywart), and some plastic plants.

I understand the little buggers are still cichlids. The male snapped at the angel one too many times and the angel snapped back. The angel is unbothered now. The problem is I think I have 3 males and he has the other two plastered, which is a bummer, because they were fine a few weeks ago until I put the sponge filter in.

Rearranged to give more cover to the victims. Seemed to calm the dominant male down a bit; he lurks under the driftwood by the sponge, waiting to snipe any fish swimming past. One of the other two must be a female because he's been trying to woo her without much success. These are neat little guys but I'm either going to have to move them or rehome them when I get my checkerboard cichlids and gold tetras, since he's not playing nice.