I am not a purist by any stretch of the imagination, but have you ever seen any mixed reefs in nature where there were no fish? I am of the school that there is something symbiotic about it and while a coral only tank may be possible, I am not sure it will thrive like it would in nature. Something about the nutrients presnt when fish are present.
i went for 6 months without a fish after my clown died.
i have now have a clown and a damsel for 4 months.
the lps's and monti's never looked better, fish do help the corals
i even feed the corals less now
From my personal experience not only dont I see any disadvantages but I think there are a few advantages. I decided to do a coral only tank because I had a really hard time feeding my LPS coral without the fish stealing all the food. After removing the fish life became much easier because I had to do fewer water changes and feeding my LPS coral without the fish competing for the food was a breeze. After a while I didnt miss the fish . . . the corals became the focal point and I realized that the corals were doing much better and growing faster than ever before. Part of the reason for that might be because of the increases copod population. Without the fish many tiny organism thrive and multiply like in a refugium but now it is happening in your tank which is great for feeding the corals.
While I dont mean to disagree with House of Laughter . . . .and I do agree with the entire symbiotic relationship . . . .I dont agree we can necessarily reproduce that relationship exactly in a fish tank. As House said there are no mixed reefs in nature without fish but on the other hand there are no mixed reefs in nature that would have the same amount of fish to water ratio that many people have in there tanks. I have enclosed a couple of picture to assure you that a coral only fish tank can and will thrive.
To summarize . . . .give it a try . . .you can always add the fish later. And if you do decided to add fish . . . .add only a few.
Thanks all for the feedback and the details are very convincing, I think I'll give it a month without fish and then maybe try a small fish or two. The coral only setup is a 24 Gallon Aquapod cube.
I can hand feed my tangs, so feeding a sun coral even at night in the dark in a 205 gallon tank wasn't working out, so I figured I'll keep a tank for corals only.