Caulerpa taxifolia, the creeping death, or not???Many web sites refer to this plant being a "killer algae". Also many forums claim that this algae can kill corals. I can't see any of it happening inside my aquarium (yet).
Many as well claim that this algae is so toxic that no predatory fish will eat it. I was observing an Emperor Angel fish eating it. Some Tangs will eat this algae also.
One thing is clear though. This algae is very invasive, and can smother other organisms if left unchecked (pruning is necessary). I am not sure this algae can release toxins (Caulerpenyne) into the water causing water quality issues, resulting stressed corals. Cynarina was the only coral affected by this algae. C. taxifolia was growing way too close to the Cynarina, meaning, they were all the time in physical contact. I believe this algae is able to sting corals, and by doing that, injecting certain amounts of caulerpenyne toxin into the coral. I removed major amount of Caulerpa, leaving behind just 4 leaves. I didn't perform water change. If it is true that this algae releases toxins into the water, corals should start reacting to it. A few weeks passed, nothing happened. All corals look great, even the Cynarina started coming back to life.
I have another theory also;
Most corals house symbiotic Zooxanthellae algae inside their tissues. This sort of algae (like any other algae) feed on: light, nutrients and CO2. I would say, since Caulerpa is absorbing nutrients much faster than Zooxanthellae, this symbiotic algae will start dying off. When this happens, corals will start releasing brown looking strings (Zooxanthellae) through their mouth. And by saying this, corals should have small amounts of PO4 and NO3 to be able to feed Zooxanthellae. This is my theorie, I am not sure is this scientifically proved.
One should know that Caulerpa needs nutrients like NO3 to be able to thrive. It is enough keeping NO3 levels between 5-10 ppm for it to grow. When NO3 is totally absorbed C. taxifolia will rapidly die off, and like any other plant/algae form, will release organics back into the water column. In this case older "leaves" become pale very fast, if this happens, take all algae out as fast as possible. To prevent this from happening, regular pruning is necessary. Growing a small amount of C. taxifolia is not an issue, but when the bio-mass increases, the algae will need up to 20x more NO3. One could dose extra KNO3, but this is not advised if a Coral Reef is in question.
I will continue observing it, and post updates.
Photos by Dusko Bojic.
