i would wait a couple more days before doing a water change, or try looking around in the tank and see if you can see wrigglers anywhere (is female paying attention to any one specific spot, or moving between two spots constantly) once you know where the fry are (if there are any) then you can do small water changes (i wouldnt do a large water change until they are a bit stronger)
she is staying in one spot and between 2 rocks there is something not sure if its the fry are they dark?