it looks like 2 of my Pandas have paired off. I have had these for just under 2 years from juveniles. I had problems over the last 6 months with a bad case of HITH with I put down to a faulty thermometer( 3 months of 34 degrees). Last week they started to pair of and have made a pit in the corner of the tank(vid attached) and they have continued like this since then. no sign of eggs.
I have also setup a stream on twitch which will be up most of the time https://www.twitch.tv/afishything