Who Gives A Fish Forums

I've got a pair of Kribs, and they've been digging like crazy - the substrate from inside and around the back of that coconut is all piled up outside the entrance. I'm wondering, are they getting ready to mate and lay eggs in there?

That's likely what they're doing. They'll probably spawn inside that coconut.

It's common for the female to seal herself in to safeguard the eggs and later larvae. Eggs are likely within the next 36 hours.