I don't have a problem with doing it - the hard part is the decision. We have another one which only has one eye, but it's growing well and eating well so it stays for now. Although if it lives it will have to live alone or with anotheer species so it can't reproduce.
I think I have spent a lot more time round animals than D - who rescues snails ansd charms spiders to pose for pictures. Once the decision is made any hesitation just worsens it is my view (hence me thinking the freezer thing is INSANE!!). They might just be fish but as long as we're responsible then I'd offer the best we could.