Man I am having the same problem, luckly not as bad. My silly self bought 12 feeder guppies, though my fish would eat tehm as they where tiny. well after 4 days i said ok there not going to eat them, and 4 had died in my filter.
So I moved them to my 10G QT tank until i could figure out what to do, and 1 month later 40 guppy fry AHHHHHHHHHHHHHHHH. I have moved the males and females into different tanks, and when they fry are a little bigger pray my LFS will take them for free.
I can see it now, one day I will wake up and there will be nothing but guppies in the tank. I want my QT tank back.
Nice tank BTW, I hope one day mine will look nice like this.