Hello. Well, seeing as guppies can get pregnant almost immediately after giving birth, having a permanently pregnant fish giving birth every few weeks is a possibility in your tank. I would look into selling the fry or separating from their parents (to prevent the possibility of inbreeding) or even selling the breeding pair of fish to another aquarium owner. The problem is only to increase as the number of fry increases, so try to choose the option that's best for you the fastest. Hope this helps.