I frequently get asked, Do your Butterflyfish pick at your corals? The answer is always the same–Yes, all the time, but I primarily keep SPS corals. Angelfish, Butterflyfish, even Tangs may take a nip at your beloved Acropora collection, but at the end of the day the net effect on SPS is minimal. Polyp extension [...]
I frequently get asked, Do your Butterflyfish pick at your corals? The answer is always the same–Yes, all the time, but I primarily keep SPS corals. Angelfish, Butterflyfish, even Tangs may take a nip at your beloved Acropora collection, but at the end of the day the net effect on SPS is minimal. Polyp extension may be forfeited when keeping fish like our polyp picking Roaops Hybrid (Chaetodon burgessi x Chaetodon tinkeri) above, however, coral growth rates, health and coloration are not. It’s a trade off for keeping such fish.
Polyp extension will still occur at night and in areas inaccessible to fish, as occurs in the wild. In many cases this will reveal the vibrant tissue of the coral that can be hidden by polyps. The Acropora horrida being grazed on in the video below is usually a brown shag rug, but as the Chaetodons pick at coral slime and polyps the underlying lavender and green tissue is exposed. (See the video in full size HD here).
One important distinction to watch for with coral nipping is what is being consumed. Aquarists often fret at any picking, but many times the coral is actually not touched. The majority of the bites taken in the video are actually getting at coral slime, and not the actual polyps. This can be difficult to discern, but can be done with careful observation. Also realize that very few fish have the specialized mouths to fully eat coral polyps.
Certain obligate coral eating butterflyfish such as Chaetodon ornatissimus and Chaetodon larvatus have specialized jaw structures that allow the extraction of coral polyps from the coral skeleton–as if plucking a hair with tweezers, leaving an empty hole in the coral. Very few fish have this ability. Most will be lucky to get just part of a single tentacle from an SPS polyp.
If you see a fish dining on SPS slime and polyps, I say nip on. After all it’s only natural.
