Many decisions are zero sum if considered in a single moment of time, but not when considered over a longer-term perspective. Obviously the thing being left out

Many decisions are zero sum if considered in a single moment of time, but not when considered over a longer-term perspective. Obviously the thing being left out is, this wasn't about saving 6 individual fish, it was about saving a handful of the surviving members of a species of fish that they're attempting to repopulate. Remember "do things that don't scale" - you save 6 fish so in a couple decades you'll be at 60,000.