Perhaps this piccie of a newly-constructed cave will help?
I then superglued moss to them.
Incidentally, I’ve seen another fry, much bigger then the one I spotted earlier – so it seems possible that there have been two clutches of eggs laid. I haven’t been able to get a decent photo of it (it’s genetically programmed to be aware of the distance it must be from a camera in order not to be photographed!)but this is the best I can do for the moment :
When I put in a second helping of green water, some mosquito larvae were included. I watched as this fry considered one for a long time. Given the relative sizes of fish and prey, I thought there’d be no way that the former could fit the latter in its mouth. Wrong!