Thanks. I've got 2 monos and 2 columbian sharks with them right now, even though they're a little hard to pick out in the photo. The only fish I've ever had problems keeping them with is target fish. They were nasty. They attacked they eyes of all the fish in my tank.
Nice tank! Do you have a problem with algae? My brackish tank is attacked by a lot of algae but maybe it's because of the high nutrient level in substrate.