hi! welcome to the forum.
doing this task isnt an easy one but generally it involves catching and holding the female while various methods are employed to coax her to release the fry. These range from having the female in a turkey baster or similar, head downwards, to release the fry through the bottom, to gently prising the mouth of the female open with a pencil... Personally I am not in favour of these methods, as I believe they all involve a fair amount of stress for the female. Some experienced breeders who use these methods say they are not overly stressful. However, it is likely that some of the techniques could take a while to become skilled at, and those attempting them for the first time might find them stressful to both fish and owner!
A better method might be to catch and isolate the female to her own small tank, and allow her to release the fry naturally. This could be a small 10 gallon tank with a heater and simple sponge filter. Add a cave or two to give her some security, and fill the tank using water from the main tank when you are ready to catch and transfer her. When she has naturally released the fry (patience required!), it would be ideal to move the female to a second small tank so that she can recover from the ordeal and be fed properly, before returning her to the tank.
hope this helps.
