I have no fish and I will tell you why I believe its better in many ways.
1. You can actually feed your corals. Most people broadcast feed their tank. Very little of this food makes it to the corals. For those that will say its unnecessary to feed corals, all I can say is that they do eat the food when you feed them. Do they not want to eat? Of course they would rather eat more! Its just impossible to feed them efficiently in a tank with fish ime.
2. Pollution. Broadcast feeding your fish and having their poop in a captive ecosystem pollutes this ecosystem. This means you must have better filtration which leads to higher expenses and more work!
3. Don't destroy the reefs. Its essentially impossible to have your fish breed and raise their young in the average aquarium. Fish have a finite live span and will eventually die. If your fish are coming out of the ocean you are contributing to the destruction of the reefs. Continuing to purchase fish is necessary to keep your system 'as is'. If you purchase only tank bred fish this is a non issue for me.
4. $$$$. Fish are expensive and will die or kill each other or be killed by something. I only had fish for 5 years before I got into coral and when I look back on those days I feel bad for the fish, most of them died but a few I sold back to a local store. They also jump out of tanks with open tops and I like open tops!
Fish are aestetic unless you breed them which cannot happen in a reef. Some do accomplish tasks like eating algea and worms/pests but these tasks can be accomplished other ways. So if you have fish in a reef go with a few of the cheapy tank bred ones and start feeding your corals!
I love fish btw
