I’m thrilled to get such a quick and definitive ID! Thank you!
Regarding fry and nesting — I never had any fry appear spontaneously in the tank (despite frequent bbs feeding), so I’ve been watching the cave (it’s a little capped PVC tube) until the fry on the nest are almost free-swimming and then pouring the tube out into a fry box and returning the parent to the original tank (or, in yesterday’s case, into a photo box.)
If you think the male won’t bother the fry (but the female will) I could try transfering cave+male into another tank and leaving them together.