I used to get around the short breaks by introducing certain live aquatic foods. California Blackworm can be very useful in circumstances like these because you can hide them around the tank (in the substrate/gravel and under the rocks etc.) for the fish to find at a later date, especially the corydoras. I also used to sprinkle drosophila (flightless fruit flies) and sprigtails on my floating plants when I went away. Sometimes too, I found that copepods and small bloodworm were excellent if they could get into the nooks and crannies hiding from the fish. Why not syringe them into the gravel/substrate. Mollys will also enjoy vegetables if they are hungry. I have been know to use everything from boiled broccoli, to red pepper, cucumber, cabbage, and especially nettles ~ at this time of year. Those cheap battery-powered automatic feeders I actually find rather awesome, especially with larger and less natural aquariums: I would just fill them with a mix of dried floating and sinking foods. I think mine cost about £7 a few years ago. If I remember correctly, they feed twice per day and will work even if you have a power cut. Likewise, a battery-powered air stone is never a bad investment when you pop away travelling during the hotter days.