Mine really like sand when compared to gravel. They also like some rockwork. I used to have alot of caves but as they grew they fought over the caves so now i just have some large single rocks in the tank. Thats working very good. I would not get more than six fronts in your 5 foot tank. As they grow you will likely have more than one male in that case you will want to keep the alpha and the females and sell off the rest. You can try to replace the extra males with some females if you want. Got any pics of your fish ?