The whole idea of working with endangered or extinct in the wild fish should be attractive to aquarists. We could actually do something.
But we are much better off pushing for funding for institutions doing this. Why?
We're looking at ourselves, as creatures with short life spans, keeping creatures that have been around for millions of years. We're like fruit flies wanting to keep elephants. We have illnesses, divorces, moves, deaths - and we have a very hard time keeping organizations together for more than a few decades. These have to be collective efforts, and we have a lot of people who really oppose the idea of doing things collectively.
There's no guarantee institutions won't lose their funding, etc. That's all political. But chances are better. We should be protecting habitats, but if you put cities in deserts and provide them with golf courses and fountains? We aren't serious.
If we were, stage two of really getting into the hobby would be keeping some unattractive little fish we want future generations to be able to look at. We'd have stud books, report to central groups, exchange species, etc. Frankly. most fishkeepers would rather keep blood parrots, GMOed Bettas, Glo-Fish, fancy guppies and other fish never found in the natural world. There are thousands of fancy guppy breeders for every breeder keeping something endangered.
For the record, I have one killie and two livebearers that are considered in danger, but I have no access to any breeding organizations, and while I distribute my fish as much as I can, none of the people I've gotten these fish to have seen them as anything other than novelties, although a few have passed them along to others.