I just discovered where the fruit flies in my house were coming from. We had gotten rid of all the fruit and vegetables in our house, yet we still had hundreds of fruit flies and their numbers weren't dwindling, no matter how many we killed. My husband insisted that they were coming from the sink somehow, I didn't believe him, but I did research it and it said yes, some times fruit flies will breed in the sweet sludge that builds up in the pipes, especially pipes that are slow moving like the little half sinks in a double sink set up. So, I plugged the drain on the slow side for a few days. The fruit fly population seemed to drop radically, we weren't being swarmed anymore and it seemed like they were going away. Then yesterday, I opened the drain and swarms of them few out. I'm not talking one or two groups of fruit flies here, I'm literally talking hundreds, and hundreds of them! Now we're back to where we were this summer with a huge infestation of them.
(That does explain why there were so many in the bathroom though)
Yuck!!!!! I know how much Fishy loves them, but there's no way I'm going to feed anymore to her now that I know where they're coming from. Yuck!!!! I just hope that she isn't going to get sick with some sort of internal thing.