I am travelling for my annual summer vacation for a week. I told this to my fish dealer he said he has that kind of food that feed the fish makes them feel full and doesn't rotten the water it last for two weeks is that true what shall I do about water change and turning the lights on and off? please heeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeelp!!! 
