Minor pet disaster...

   Tonight, the kids were playing nicely together in Colin's room.  They were playing with trains, taking turns, and seemed perfectly happy.  It was a beautiful Spring day, and I decided to walk out onto the front porch, and let our dog Abby walk around the yard for a potty break.  It was so pretty, I sat down in one of the rockers, enjoyed the weather, and listened to my children playing through the open windows.  Abby was wandering around, looking for the perfect spot, when I heard the sounds of trouble brewing.  It started with a simple "No, No Molly."  And quickly advanced to "Mommmmyyyy!!! Molly is feeding the fish."  This can't be good...I trotted into Colin's room to discover that Molly has emptied, yes I said emptied, the entire container of fish food into the ten gallon tank.  She looks at me with her glowing smile and says "Mommy, I feed the fish." Oh my, I launch into disaster containment.  I start scooping out the fish food manually with the net, and realize quickly, I have no idea what I actually need to do with this situation.  I grab the tank vacuum, and siphon out about half of the water.  It was about this time that I realized that in my panic, I had left the dog outside.  Just as I suspected, the dog was no where to be seen, at least not in the immediate area.  Luckily, we have the best dog in the world, she always comes back.  Even though she does occasionally bolt when she senses an opportunity.  I move into "find the dog" mode, and after a few minutes of standing on the porch and calling for her, Abby appears, with her tail tucked between her legs.  Back inside to deal with fish disaster.  I treat some more water with water softener stuff, and pour in fresh water.  I can tell now, that the problem is much worse than I thought.  I apologize to the fish, say a little prayer that they make it through this disaster, and wonder to myself how difficult it will be to find replacements for Dorothy and Dogfish while the kids are in school tomorrow.  I really have no idea how to get out all of the food residual in the tank.  Any tips are appreciated.  This is our first fish tank in the house.  I am guessing a complete water change is in order, but they always recommend against that.  If they make it through the night, without eating themselves to death, what is my next move??  Fish tank advice, anyone??