I keep my adult male at 77-78F, which seems to work best for him. I tried low 70's when I had a heater fail, and he became a LOT less active, went off his feed, and his nuchal hump shrunk down. I kept him at 70-72 for 2-3 months (over summer), and then finally replaced the heater. Within a few days he was back to his old self. He clearly appears to be more comfortable at 78.
The following is from a past post of mine on this subject........
I personally don't think that a fish suffers, if kept at a middle ground temp, somewhere between what would be found in winter, vs summer. That is typically how I run my tanks, and this seems to work best especially if the tanks are mixed species (gasp), or mixed continents (double gasp). I recalled an old thread on cichlidae on Herichthys, and the temp that one individual kept his carpintis male.
https://www.cichlidae.com/forum/viewtopic.php?t=5919
I don't agree with that, anymore than I agree with keeping that species at 80F year round. A fish kept in cooler water, fed less, and that lives longer does not necessarily equate to a healthier, or happier (fill in the anthropomorphic blank) life.