None of us can save a fish from extinction. Maybe,just maybe, all of us could keep one around. But if we destroy the habitat, we have to ask what the life of the species is.
In 1992, I got a pair of killies whose only known habitat had been turned into a palm oil plantation. After a lot of research and networking, I discovered I had the last pair in captivity. Now, after more than 30 years, I have 7 tanks of them, breeding and surviving. A couple of years ago, farther up the one river they had been found in, a short ravine was fished, and they were found again, protected by the terrain being completely unsuitable for farming, and the ravine being steep and hard to get down into.
I can talk til I'm blue about the importance of that habitat, but on the ground, there is an agricultural corporation run for shareholders who have probably never even seen the plantation and who don't even know where their money comes from. Only geology and luck have saved the species.
Meanwhile, I have given dozens and dozens of pairs to other killiekeepers. I've mailed eggs to three continents. To my knowledge no one else has taken on the idea of maintaining them. They keep them, get bored, and get something else. As fish breeding has become less popular, fish like this end up vanishing from the hobby.
I like keeping them, but I will be lucky to live another 20-30 years, and as I age, I don't know how long I'll be able to run things. My predicted lifespan, like yours, is somewhere in the 80 year range if you live in a rich country. It's foolish to think a creature that lives 85 years can save a creature that has existed for hundreds of thousands of years. We're like fruit flies keeping tortoises.