It is a very worthy cause, we need to maintain species that are threatened in the wild. If we don't, then future hobbyists will surely be disappointed. Check out the website, the link is below. Here you will find the list of fish that CARES has determined need help. Hobbyists then register the species they are keeping. If you are looking for a particular species you might be able to find a hobbyist(s) working with it and be able to obtain fry. You may have fish already that are on the list. Its all about maintaing a list of who is working with what and trying to keep these species in the hobby.
Recently there has even been talking about trying to re introduce some species that have been overfished for the ornamental hobby. Unfortunately re-introduction is not an option in habitats that have declined, such as Lake Victoria. http://www.carespreservation.com/priority_list.html
Let me know if you have any further questions.