How to FEED your reef tank so that your corals will really GROW, instead of ho-hum...

[capecoral]

With my fascination of reefs from watching tv, I have since been doing a ton of research (I knew I went to school for something!) on how to eventually have a nice reef tank. While I don't have the money to set it up yet, I do have the time to research how things actually work, and what will be needed for it. Lucky for me, a college buddy of mine was studying marine biology, and we have kept in touch ever since. He is now working with a group that is doing advanced research on coral reefs, and he was nice enough to give me some coral feeding info that they are putting together for hobbyists. He said I could post the info if I wanted, as it gets written. He also said they are trying to simplify it, to make it easier for us to understand (no complex numbers, references, researchers, etc.) So here is the first part... hopefully it will help you feed your corals, and mine too when I get some:

WHAT HAPPENS TO MOST CORALS: Reef aquariums are probably the most amazing thing you can have in your living room, and they really impress almost anybody, even if the tanks have only fake plastic corals. But reef tanks owners themselves are only impressed if they are successfully keeping real corals, which means of course, that the corals are not dying. Further, reef tank owners are even happier when their corals are actually growing and getting larger. The happiest moment for some hobbyists is when their corals are reproducing and showing up in new spots all over the aquarium where they never were before, just like corals do in the ocean.

In the real world of reef tanks, however, many corals die, or get covered with algae; they don't grow much (compared to the ocean), and hardly ever reproduce in remote spots in the aquarium (except for mushrooms, etc). If the corals grew like they did in the ocean, a three year old reef tank, started with only frags, would be packed to the glass and sticking out of the top from just the growth and reproduction of those original frags. Some hobbyists do know how to grow some corals, but they do so with lots of experience and equipment. No hobbyist, however, has been able to keep all coral types alive, much less keep them all growing and reproducing. So this info is designed to show you why this is, and maybe for the first time, to change it for the better.

CORALS NEED FOOD: If I were to tell you that I just bought a fish that lives on sunlight alone, and does not need food, you might be disappointed that someone lied to me at the fish store. But this is how many reef hobbyists think about their corals; they think that corals live on light alone, and that the corals do not need feeding. This is exactly the opposite of how it really works, and is the reason that their corals do not reproduce, grow, or even stay alive in some cases. In the ocean, there are no (zero) corals that live on sunlight alone. There are, however, corals that live on food alone, and which don't require sunlight. So, what exactly is this food that corals eat?

Corals eat PLANKTON. And the more plankton that is flowing in the water, the more that ALL the corals will grow. This is not the case with light: Corals need various amounts of light, but they will not grow more if the light increases past a certain point. With plankton, however, there really is no limit to the growth. Corals grow faster in the ocean when there is more plankton, and they grow slower when there is less. But most hobbyists have very little plankton in their tanks, if any at all, so sometimes the best they can hope for is that it's enough to keep the corals alive. Some hobbyists will mess around with the lighting, thinking it is the cause of slow growth, when actually it is just the lack of food.

WHAT PLANKTON IS: Plankton is the stuff that floats in the water. It's the stuff that looks like dust or dirt, or like little bits of trash. The bits can sometimes be so small you can't see them, or they can be as large as a pinhead. And they can be either alive or dead. The important part is, they FEED your corals. Yes, corals eat both the living AND the dead stuff that floats in the water. Here are some details on the types of plankton:

Zooplankton: These are little living animals, mostly little pods. Just remember "zoo", as in animals at the zoo. In the ocean, most of the zooplankton is copepods, which are as small as a grain of dust, or as big as the point of a pencil. Other zooplankton are rotifers and mysis. Ocean reefs are packed with zooplankton. Zooplankton is the major food of corals, and many small fish too (many baby fish eat only zooplankton).

Phytoplankton: Phyto mean "plant", and these tiny things are microscopic bits of plants that float around the top part of the ocean (about 300 feet deep, across 70 percent of the earth). They are actually algae, and they are the most important living things on the planet. They are 90 percent of all living life in the ocean (besides bacteria); they feed everything in the ocean, and they produce all the oxygen that you breath. Without phytoplankton, everything on earth would die (except maybe bacteria). Phytoplankton are so small that you cannot see even billions of them. Matter of fact, the crystal clear reefs that you think are "pure", are actually loaded with huge concentrations of phytoplankton in the water.

Detritus: Pronounced similar to "just-TRY-us". Detritus is stuff that used to be alive (zoo, phyto, fish waste, coral waste), but now is dead. Reefs have more detritus floating around than any other part of the ocean, so detritus is a major food for corals.

Bacteria: The number one life form on Earth, including in the ocean. Bacteria is very active on ocean reefs, and it feeds lots of corals, although not as much as zooplankton.

HOW FAST DO CORALS GROW IN THE OCEAN: Fast-growing branching corals, like staghorn acropora, can grow 8 to 10 inches (20 to 25 cm) per year in length. Here is a sample report:

Geoscience Research Institute
http://www.grisda.org/origins/06088.htm

"Most polyps at 66 cm from the tip will be approximately 7 yr older than polyps at 3 cm from the tip" [this equates to a linear growth of 9 cm per year; a frag that is small today would be 18 cm in diameter (7 inches) in one year.]

"Sewell (1935) reported 280 mm/year [11 inches] in the Andaman Islands in the Bay of Bengal, and Verstelle (1932) reported a maximum rate of growth of 414 mm/year [16 inches] in the Celebes."

"The fastest growth rate reported for any coral is the staghorn species Acropora cervicornis. Lewis (1968) found in Jamaica a maximum rate of 264 mm/year [10 inches]. Shinn (1976) studied the growth of this species following destruction in a hurricane near Florida. He estimated linear growth rates of 100 mm/year [4 inches]. He also found that because of the branching habit (several new branches added to a single previous one), much more than the linear growth of a single branch is involved in establishing a dense stand of this coral. Under these branching growth conditions, carbonate production [growth] would be more geometric than linear, and could contribute further to the carbonate mass [size] of the reef. Gladfelter, Monahan and Gladfelter (1978) report rates of 99 mm/year [4 inches] for Acropora palmata in the Virgin Islands."

And here is another study:

Growth Of Acropora Pulchra in Bolinao, Pangasinan, Philippines. Proceedings of the Fourth International Coral Reef Symposium, 1981:

"If mean monthly growth rates for all [test] sites are averaged, they can be extrapolated to obtain a mean annual growth rate of 18.1 cm/year [7 inches] for Acropora pulchra. 22.58 cm/year [9 inches] was obtained for the same species at Yap Island in the Western Pacific, in a study that covered only the cooler [slower growing] months of October to December."

Mean growth rates of Acropora pulchra control colonies:

Date -- Mean Growth Rate (cm/month)

10/80-12/80 Site A: 1.8 Site B: 1.6 Site D: -
12/80-01/81 Site A: 2.3 Site B: 2.0 Site D: 1.5
02/81-04/81 Site A: 1.4 Site B: 1.3 Site D: 1.2
04/81-05/81 Site A: 0.6 Site B: 0.8 Site D: 0.6


HOW TO FEED YOUR CORALS: To achieve growth like in the ocean, corals need to be fed like they are in the ocean. Most all corals do use sunlight, and this is called Autotrophic feeding. Auto means "self", and Trophic means "feeding". Sure enough, the corals use the sunlight to "make" some energy for themselves. Most all aquariums have enough light, especially reef tanks, so fortunately this is not a problem. Most of the energy from sunlight, however, is only used to keep the corals alive; very little is used for growth and reproduction, which is what we want.

The second type of feeding is call Heterotrophic. Hetero mean "different", and sure enough, corals also eat food that they don't make themselves. Matter of fact, this is how corals get most of their food, especially when it comes to growth and reproduction. This food can be any of the plankton listed above: Zooplankton, phytoplankton, detritus, and bacteria. It's the zooplankton that does most of the feeding; and since zooplankton is actually alive, the corals are said to be "predators" of the zooplankton. It's kind of weird to think of corals as predators, but if you ever get a chance to use a microscope to watch coral polyps (especially SPS) use their chemicals to zap and eat pods, you'll understand. A polyp senses a pod (some polyps actually chase pods), and then it stings the pod with chemicals; it then wraps around it with a sticky net and pulls the pod into the "stomach" of the coral where the pod gets digested over the next couple of hours.

This digestion part is important, because a polyp cannot eat again until the initial food is digested. This is why you want to supply food to corals 24 hours a day, especially at night, which is when most feeding occurs in the ocean. If you just try to target-feed your corals by blasting them with (any kind of) food, only the first few particles that hit the coral will get eaten and digested, and all the rest will go to waste. So if you are going to limit coral feeding to certain times, make sure it's at night, or else the polyps won't catch enough. But by far the best technique is 24 hours a day, just like they eat in the ocean.

SUMMARY: With some slight changes in your feeding techniques, you can multiply the growth of your corals many many times, and even get them to multiply/reproduce in remote parts of the aquarium where they never were before. And maybe you can also help save corals from extinction, starting with the Acropora cervicornis "Staghorn Coral", and the Acropora palmata "Elkhorn coral", which are already almost gone (95 percent extinct, due to environmental changes) and are not expected to be around much longer in the ocean.

Lastly, here are two plankton videos that we found on youtube, which do a pretty good job of describing what plankton is:

http://www.youtube.com/watch?v=LuXMz3j9E8k
http://www.youtube.com/watch?v=A9AKf6OnuPg

And here are pics of the corals talked about:

[Threelittlefish]

Nice write up.... Who is the author?

[b_s_c1]

Very good information. I just have one question. How do you suggest we keep a constant food source of phyto or zooplankton in our tanks at all time?

[sslak]

Phytoplankton is alive too....

Do you have pictures of your reef tank and growth measurments to back this up?

I would love to see how your corals do under this type of feeding regiment!

How do you constantly feed phyto/zooplankton to your corals without compromising your water quality?

[iap]

It's not his article. It's a friend who is a marine biologist. The op hasn't set a tank up yet.

[frankpayne32]

Good information but nothing new I'm afraid. Most reef hobbyist know that corals are both autotrophic and heterotrophic. Also, most of use know that it is best for the corals to have a constant supply of zooplankton and phytoplankton to eat but in our limited systems with limited filtration this is at worst impossible and at best extremely difficult.

[jchase1970]

"most corals feed at night" - is this true? in my tank everything closes up at night.

[mdb_talon]

Originally Posted by jchase1970

"most corals feed at night" - is this true? in my tank everything closes up at night.

Yes it is true. Corals will adapt to the environment though also. If they are accustomed to being fed in the daylight then many will eventually switch to some extent. Personally I feed mine right before I go to sleep (about an hour after the lights go out) and first thing in the morning which is still several hours before my lights come on.

[dogstar74]

Very good write up, but you can't just dump chicken soup in the tank daily, and expect it not to foul. While I think the benefits of heterotrophic feeding are numerous, I think the biggest detriment would be increase in detritus and nitrate and phosphate production. This would quickly cover the zooanthela (sp?) and starve out the autotrophic mechanism, and dilute the colors of the corals. The covering of algae would kill the coral by preventing the pods from reaching the polyps in the first place, and the coral will die.

I understand the benefits of haveing a constant supply of microfauna, but history in the hobby has shown the far reaching detriments. And if I can have crystal clear water, sterile even, and have a tank 1/2 as nice as most of the TOTM, then I'm willing to have slower growth rates.

I am very interested in a regimen though that would boost growth. Spot feeding zoas, with whatever they need to grow would be a good start.

I think this area of science really needs to be studied for the good of the ocean as well as the good of the hobby.

Aaron

[sslak]

+1 dogstar

The write up make sense, but I can't see how it applies to the hobby.

There are no instructions or ideas about how to implement this, nor is there proven success with such a method.

[LobsterOfJustice]

1. The are absolutely corals that exist solely on light alone. Many Xeniids have pretty much lost their stinging cells and digestive systems, thats just one example.

2. Reefs are not loaded with phytoplankton. That is why the water is clear.

3. Bacteria and detritus are probably the number one food source for corals (especially SPS), not zooplankton.

[dogstar74]

Originally Posted by LobsterOfJustice

3. Bacteria and detritus are probably the number one food source for corals (especially SPS), not zooplankton.

I'm not being argumentative, but I'd like to see a reference on this statement. I wonder if that is why all my corals close up after I stir up the tank. Maybe rather than being really mad at me disturbing things, they're just eating everything that's floating around. I do know they usually look happier the next day when things have finally settled down.

I wonder for those of us who are land locked what alternative to freshly harvested plankton there may be.

Aaron

[Toddrtrex]

Going off of what "LobsterOfJustice" said, I had a tabling milli that went from a 1.5" frag to a 12+" colony in about a year with 0 "PLANKTON" added to my tank. Just used my lights and whatever waste my fish produced.

[LobsterOfJustice]

Originally Posted by dogstar74

I'm not being argumentative, but I'd like to see a reference on this statement. I wonder if that is why all my corals close up after I stir up the tank. Maybe rather than being really mad at me disturbing things, they're just eating everything that's floating around. I do know they usually look happier the next day when things have finally settled down.

I wonder for those of us who are land locked what alternative to freshly harvested plankton there may be.

Aaron

I'm 3/4 the way to a Marine Bio degree with oceanography minor. Learned it in class. I would absolutely say that they are closing to feed.

[ReefTeacher]

So PE is not related to feeding? I really never knew that. Why do we add Amino Acids and the like for PE?

[larrynews]

the biggest thing i did was just stop moving them around, and they started growing my monti caps grew noticeably every week

[Jaycen B.]

Keep this going I want to know more please.

[capecoral]

Holy fish poop (yes I just learned that poop is coral food)

Hope all this can be figured out by the time I get my 55 up and running.

[dogstar74]

Originally Posted by LobsterOfJustice

I would absolutely say that they are closing to feed.

That's excellent news. Here I always thought it was a protective response and that they were all really mad at me.

I wonder what this forum would think about using blood as a coral food? Red blood cells are appx 8 microns in size. And while they are not the best source of protein they do have some proteins that I'm sure biological organisms would eat. Blood is plentiful, and can be relatively easy to get. The saline in our tanks nearly mimincs the human osmolality so they would stay intact for quite some time, at least enough to find their way to a coral or other filter feeder.

About the only thing I can think they would be missing is the calcium in the exoskeletons of the plankton.

.....discuss.....

Aaron

[Gary Majchrzak]

Originally Posted by capecoral

Detritus: Pronounced similar to "just-TRY-us".

detritus is pronounced just how it looks

detritus is usually plentiful in a closed system (reef aquarium).

if FEEDINGS were the only key to rapid coral growth then the person(s) that dumped the most food into their reef aquarium would have the fastest growing corals.

[Gary Majchrzak]

Originally Posted by capecoral

Holy fish poop (yes I just learned that poop is coral food)

Hope all this can be figured out by the time I get my 55 up and running.

the 55 is your first reef aquarium?
load it up with lots of pooping fish and let us know how fast your corals grow.

anybody that's done a 24/7 phyto drip can tell you how fast it can grow algae.

[Gary Majchrzak]

Originally Posted by Jaycen B.

Keep this going I want to know more please.

is the brain coral in your avatar in your reef aquarium?

If so, have you ever shined a flashlight on it at night? Ever try feeding it? More importantly than feeding it... do you monitor the water quality in your reef aquarium and make sure alkalinity, Ca and Mg are optimal while keeping phosphates low?

[Aquarist007]

B]Some Feeding Recommendations for Corals and Inverts[/B]

Cyclop-Eeze:

SPS corals
Feather dusters
Zoanthids & small colonial anemones

Sweetwater Zooplankton:

Zoanthids & small colonial anemones
Large polyp stony corals

Phytoplankton:

Clams
Feather dusters

Larger plankton substitutes such as frozen Pacifica plankton and Mysis shrimp:
Large polyp stony corals
Anemones

Sushi Nori/Seaweed Selects:

Snails
Urchins

Rotifers (live and prepared formulations):

SPS corals
Feather dusters

http://www.reefkeeping.com/issues/20...ture/index.php
Steven Pro

[fantastic4]

Thank you, very good read for me, will take this knowledge and apply to my tank.

[Paul B]

I hatch brine shrimp every day and put it in my tank twice a day. I know it is a little larger than a lot of plankton but I don't have many SPS corals anyway. I do have gorgonians that do eat the new born brine.
In the summer I also collect plankton to feed the tank but I realize most people can't do that.