No water changes while being away for three weeks? / Preparing food for vacation substitute
Is it possible to run a 60 cm aquarium for 3 weeks without a water change?
yes, this is possible if basically everything is alright (no diseases, fish well conditioned, no basic fish stock or water problems).
I will be abroad, a holiday substitute would feed every other day.
I have an advice on how to do it best: Prepare food portions in advance (plastic film cans from a photo shop are well suited) and write a date on them, lock away all other food! At least people who have no experience with aquariums tend to feed way too much, and this is much more dangerous than feeding somewhat sparingly. This, however, does not apply for juvenile fish and a few species that really need food daily (or even several times a day). In such cases, an automatic feeder is a good solution.
Dr. Bodo Schnell