I had a first time lab mom who I thought was holding unnecessarily long and I was worried about her health. She was in the main tank and I had no chance of catching her. It was suggested I build a "fry pile"-- a small mound of smaller rocks (I used river rocks) that the babies could hid in but the rest of the tank couldn't get in. So I did, and one day latter, mama spit into the pile. I ended up with two babies from her first spit and one from her second. You might consider it. Some day I hope to get rid of the pile, which is wrecking my tank asthetics, but not yet!