If you do small water changes of 10% then your be ok if the water is similar.
If you need to do larger, then you have to watch the temperature's to make sure it's not changing to quickly.
Once their about 2 months i happy doing 20-30% changes.
Actually, if you want optimum growth, you will do lots of water changes for your livebearer fry. As long as you are careful to match things well, a water change of even 20% every other day will go a long way toward promoting good fry growth.