A quick and easy way to get some basic information on fish is to google (or comparable search) : cockatoo cichlid profile . Just type out the name of the fish your interested in followed by the word profile (all with no punctuation). From there I wouldn't rely on any one sites info, but you will have pages and pages of sites to look at. Compare three or four sites and find the consistent answer.
I did this for cockatoos just now and found a pretty huge range if you tallied up all the sites I checked. But it all boiled down to high 70s(78F-79F). With most fish (not sure if it applied to cockatoos) increasing the temp helps to induce breeding. I keep all my cichlid tanks at 80.5 F. No scientific reason why I picked 80.5, that’s just the temp my biggest tank balanced out at and I wanted all my tanks consistent (makes it easier to bounce from one tank to another that way).