Ya I was going to say they will be fine but given your stock...whats the size range on the beasts again?
X2 I agreeThree weeks is a long time the instinct of survival would kick in you will come back to someone being killed or eaten please try to trust someone to stop by to feed.
I would pre-package a set amount in a container and label it for what day to feed them. I also made a note that if my family/friend missed a day... not feed the missed day. I never had any problems.
And also asking someone to come in and put out food is not an option
This is how I do it too. 3 weeks isn't usually a problem. I don't feed fish every day when I'm home. I have witnessed some of the more agressive fish will bully. I believe that isn't because they need to eat, they have left their food coma.I've been away for 3 to 4 weeks at a time without feeding my fish. Unless they are fry size, fish are cold blooded animal and can starve for weeks with no long term ill effect. Remember many moutbrooders and breeding fish won't eat for weeks to incubate eggs. Without feeding, the water quality will be maintained at optimum condition and dead fish will quickly be consumed. Asking friends to feed your fish may do more harm than good by polluting the water.