The importance of feeding your SPS corals

[Achilles Tang]

SPS keepers, read this!

I'll pick out some statements which jump out the most:

C.M. Yonge was the first to demonstrate that zooxanthellate corals (many diverse species) could survive "indefinitely" if provided with adequate zooplankton, even if totally deprived of light. In contrast, corals provided light and deprived of zooplankton did not survive.

Many other studies confirm the predatory abilities and requirements of "SPS" corals. It should not be surprising given the fast growth rate and fecundity of many small polyped species. In other words, more growth and reproduction requires more energy, especially nitrogen for tissue growth.

Finally, I have provided a column that shows the percentage of feeding on zooplankton compared to feeding on bacteria or dissolved organic material. Once again, there are no obvious trends except that some species rely more on zooplankton than others and that, if anything, the "SPS" corals feed on zooplankton a lot. In fact, most corals show linear feeding saturation dynamics under all but extremely high particle concentrations. What this means is that corals have a hard time "getting full." They continue to capture prey and do not get satiated until prey densities become so great that such levels are almost never possible. To put it another way, even if you were to pour a pound of food per day into an average sized reef aquarium, the corals would still "be hungry."

Many years ago, one of the only complete energy budgets for a coral was done for what might be considered the ultimate shallow-water "SPS" coral, Acropora palmata (Bythell 1988, 1990). The study showed, basically, that 70% of this coral's nitrogen needs were met by feeding and that 91% of its carbon needs were met by light. At the 2002 conference, Bythell et al. examined three more corals, the larger polyped Montastraea cavernosa, M. annularis and Menadrina meandrites. They found zooplankton to provide 20-80 times the carbon and 112-460 times the nitrogen previously shown for Acropora palmata. Finally, Fanny et al. (2002) investigated the role of zooplankton consumption on the metabolism of the small-polyped coral, Stylophora pistillata under 3 different conditions of light (80, 200, 300 µmoles m-2 s-1) and 2 feeding regimes (Artemia and natural plankton). They found that regardless of light, fed corals had higher chlorophyll a concentrations, higher protein levels, and had photosynthesis rates 2-10 times higher than those deprived of food. This group also measured calcification rates, both in the dark and in light, and found that calcification, as is well known to be the case, is enhanced by light. However, for the first time it was shown that feeding results in calcification rates 50-75% higher than in control corals (not fed). It was also found that feeding does not affect the light-enhancement process of photosynthesis on calcification. To make these results completely understandable, if corals can feed on zooplankton, they will calcify 50-75% faster irrespective of light levels provided.

Phytoplankton, while a very beneficial addition to aquaria, does not feed most corals (Borneman 2002). Something as significant as zooplankton to both coral and coral reefs would seem worthy of the highest efforts in trying to produce, add, grow, substitute or in some way provide to tanks. I cannot think of a single greater accomplishment and advance for aquarists than to provide by whatever means (higher export and higher input, larger refugia, purchase, plankton tow, culture, etc.) significantly greater levels of zooplankton or zooplankton substitutes to their corals.

[RAV-65]

One question : Will feeding more zooplankton result the water to be more "polluted"? like feeding the fishes? until now, i dunno if the corals actually pass motion? maybe a stupid question to some, but i really dunno... maybe they dun produce waste which results in ammonia like fishes, but do they produce anything else harmful?

Vincent Ho

[Achilles Tang]

RAV,

If you feed live zooplankton like live rotifers, only when they die, they will pollute the water. But because they are so tiny... I highly doubt if they will affect the water.

If you feed zooplankton substitutes like Golden Pearls, which is essentially protein powder, they will also eventually break down and decompose.

I consider 'liquid coral food' the worse culprits for water pollution when it comes to food. If it is not consumed or is broken down too quickly... it will be skimmed out in time or in a worse case scenario, fuel cyanobacteria or nuisance algae growth.

Every living creature has to respire and produce metabolic wastes, fishes, anemones, corals and even bacteria.

That is why I advocate people to buy the best skimmer they can afford so no matter how much they feed, that insurance (a good skimmer) will be there to keep the water from being too polluted.

[RAV-65]

AT,

thanxs for the comprehensive explanation, I'm a strong believer of skimming too, juz dat I find dat certain skimmers are way overpriced... i'm still trying to find a skimmer dat's effective and reasonably priced, dat price could be a couple of hundreds, but important thing i find is that the skimmer's perfomance must match its price....

In your opinion, any skimmers fit the description?

Vincent Ho

PS : tink i stop using liquid coral food from on... but basically, i tink they are juz zooplankton, so i guess i'll juz use DT from now...

[Achilles Tang]

Suggest you talk abt skimmers in a new thread. It's totally off topic here.

Liquid coral food is usually poo-pooed by serious hobbyists who question what really goes into it.

Lab tests have actually shown two popular liquid coral food to have almost zero nutrititional values ie. almost just water!! It is suspected that it's just yeast added into it. Oh well. *shrug*

[Jackson6745]

Achilles Tang,

FWIW All my acros and even some monti's eat the froze cyclop eeze. I have been feeding CE for the last 2 months and I have seen an increased growth rate but I'm not sure if it's from CE or the reactor I added at the same time

BBut anyway, there was a whole thread on reefcentral about this. Here is a pic of a pocillipora consuming CE

[Achilles Tang]

Hi Jackson,

Yeah I read it. The jury's still out concerning whether the polyp capture means its actually gonna ingest it or spit it out. Acro polyps apparently capture anything suitably sized, even tiny plastic beads.

I certainly hope that they will eat Cyclop-eze too! Hee hee!

[Jackson6745]

I actually watched an acro catch the CE, hold it, suck it in, and then it was gone. The CE was defenitely taken in.

[FuEl]

Makes sense..considering sps corals are in the phyla cnidaria

If I din remember wrongly from my lectures all cnidarians possess nematocysts. Surely used for prey capture. Think of it, sps like the acros are found in such pristine waters that have very low levels of nitrates (or even none at all)...they would have to obtain nitrogen for protein synthesis somehow. I don't think they are nitrogen fixing to obtain dissolved nitrogen gas in the water. Their main source of nitrogen would come from prey like zooplankton in the form of protein. Which explains why sps can be seen extending their polyps during the night..to capture the zooplankton upwelling that occurs during the night.

Come to think of it..came across an article before..but forgot the address..was mentioning that since most sps reefers might have trouble sustaining a healthy zooplankton population in their tank due to inadequate feeding etc, a little nitrate in the water might be able to supply the coral with the necessary nitrogen for protein synthesis.

A point to ponder about...

[FuEl]

Decided to contribute some material from my lecture notes...since this topic is on feeding sps...should be plankton related right?

ENJOY!

3 types of plankton exist : Zooplankton, Phytoplankton, Bacterioplankton (minute bacteria and cyanobacteria! )

Classification of plankton

Smallest plankton are femtoplankton (0.02 to 0.2 µm)

Largest plankton are called megaplankton (above 20cm! )

Alot of other classification in between..

Phytoplankton

Large phytoplankton consists of : diatoms and dinoflagellates

Smaller phytoplankton consists of : Haptophytes and Cyanobacteria

Newly discovered phytoplankton : Prochlorophytes (estimated to contribute up to 1/3 to 1/2 of total ocean productivity)

Zooplankton

Crustaceans incld. copepods make up 60-70% of all zooplankton.

THE MOST IMPORTANT GROUP OF GRAZERS IS THE COPEPODS AND THEY ACCOUNT FOR 70-90% OF THE HERBIVORE BIOMASS

Most larvae start as phyto-grazers and might become carnivorous or omnivorous later.

Ok..think I stop here...later AT tekan me.. Maybe someone should invent a diatom reactor ###### copepod refugium connected to the main tank.