All of my fish, including rabbitfish, tangs, amd angels receive daily dose of varied diet including lots of protein, fat, and fiber

I do have an orange shoulder tang in here

Funny you ask- In the beginning I did, faithfully weekly water change. And then the parameters just keeps moving up and down with that. As of late, the only water change I do is when I do deep sump cleaning to remove any sludge, or when I perform any re-scaping. And the tank parameters are actually more stable without the changes. So the short answer is yes I do occassional water change only for maintenance. But not at a regular cadence.