Ours are breeding all the time now. We have had a couple of discoveries like yours but until recently we thought they were dieing off or getting eaten. Just yesterday we found 3 or more in the fuge in the sump and in two different sizes. From what I understand they are easy to raise. The only difficulty is feeding them food they can eat. I was told by a member here who breeds them regularly to use prawn roe for food and feed as often as you can. Ours have been surviving all on their own in the fuge undoubtedly eating baby pods and the like.
Very cool and good luck with them.