Scenario: You have a giant tank with giant fish, (pick one, say, catfish) and something goes wrong with the tank and you dont have adequate back up accommodations for them.. what do you do?
Gee I guess that depends on what went wrong with the tank. I not sure why you even put release them as that is not only illegal but very harmful to our hobby; and at the very least not MFK at all.
If the problem with the tank can be corrected quickly I would say try to keep them I am sure you love your fish and would hate to lose them. If its not something that can be repaired in a timely manor you need to do what feels best to you. If you give them to a LFS maybe they will get a good home, after all that where we all get our fish; so its not 99% chance they will go to bad homes.
youve given some pretty horrid choices, but in reality they are mostly whats available to people. Ideally, buy as many tanks needed to house them...but that is obvious and if something went wrong and your could not afford to fix it you probably couldnt afford to buy all these new tanks. I would say destroy the fish, I would say eat them but alot of water treatments used are not to be used on fish intended for human consumption.
thats if giving away to LFS or good home is NOT an option.
I just keep money set aside so I can get a new tank right away if something where to happen to their current tank. And preformed ponds are super cheap and come in very large sizes if you need something to hold them.