Yes for sure that smaller one is the female. My male spent hardly any time in the cave but patrolled the surrounding area. My pair dug a much deeper hole, and the eggs were placed right under a rock ledge at the bottom, with just room for the female to get under, not the male, though he somehow managed to fertilize them. I never saw the eggs or wrigglers, only the fry when they became free swimming - which took longer than I had expected actually. They spawned again but I am away at the moment so not sure what stage they are at now.