So I've had a colony of 12 neolamprologus similis for about 1 month now in my 75 gallon tank. There are around 5 shells per fish ranging from 2.5" to 1" in diameter. For the past day or so, I've noticed that one of the smaller similis, most likely a female, has been pushed to the top of the tank, hiding out by a piece of driftwood and a heater. Any time she attempts to go downwards, the other fish immediately come to chase her away. There is a relatively secluded spot with some shells in it on the opposite corner of the tank, and I have considered trying to move her over there in order to get her a new place to stay. The problem is this: how do I catch her? They're all very quick, and can easily hide around the driftwood or rocks in the tank, making it near impossible for me to transport her from one end of the tank to the other. Is there anything I can do to try and catch her more easily, or am I condemned to removing all of the hardscape materials and replacing them in an effort to catch her? Or is there another way for me to help her? Any input is appreciated.