Back in my early years....I quarrantined lots of 50, small goldfish in half cut 5 gallon Alhambra bottles....I would throw in an airstone and feed the feeders crushed flake once a day....Maybe 10 would die in the first die.....But 50 would not last me for a week, due to my hungry folks....
These days, I breed my own feeders in seperate tanks....Not goldfish, but Convicts....Lah-dee-dah,lah-dee-dah....