After you have sorted out your problem then I would seriously consider getting a UV sterliser.
I can't recommend any specific meds as I've never had this particular problem. In fact I've had no problems whatsoever since I've started using a steriliser.
Please post your question in the tropical emergencies section.
Forget that request, I will now move your post there. The livebearer section is not really set up to handle health issues.