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coral feeding

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mojoreef

Reef Keeper
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Jul 5, 2003
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I did a little post for a fellow on another board, and I thought I would share it here. feel free to ask questions if you need clarifications or if ya just want to talk about it.

There are various feeding mechanisms used by the inhabitants of our
reef aquariums. In some instances the same organism may use more than one feeding strategy which is probably an adaptation to ensure that as much nutrition as possible can be extracted from the nutrient poor area that a reef is. This is the case with many coral species.
Filter feeders feed mostly on detritus and fish waste. Those that feed on detritus either digest the bacteria living on them or the particulate organics that coat such particles (Wotton 1988). Will they feed on rotifers? yep do they need them in place of the above? nope.
Organisms (sps/most lps/ most soft corals/ feather dusters and so on)that feed on smaller particles such as detritus and its associated components, as well as zooplankton, can either be fed or, in some cases, ignored entirely. Given that large amounts of detritus are produced in reef systems and that this detritus is often found as a fine suspension in the water due to the actions of burrowing worms in the rock, fish, bacterial action and water movement, most filter feeders receive more than enough to eat and do not need any additional feeding.
Zooxanthellae bearing corals (hermatypic), both hard and soft,
including mushroom anemones, zoanthids, anemones and gorgonians, can utilize a wide variety of feeding techniques. Not only can they
utilize the photosynthetic products of their algal symbionts but they
can also feed directly on plankton, bacteria, detritus and fish feces.
Some corals have even been shown to be able to directly absorb glucose from the water (Stephens, 1962). Other zooxanthellae bearing organisms include some sponges and Tridacna spp. clams. the general consensus is that zooplankton do not contribute a major portion of the caloric or carbon requirements of hermatypic corals (Muscatine and Porter, 1977).
The general rule seems to be the smaller the polyps, the more
important zooxanthellae are in the diet (Porter, 1976). Corals
feed in a variety of ways. The larger polyped forms (e.g. Euphyllia
spp.) can actually feed on shrimp-sized prey which they capture with
their tentacles. Other forms collect the slime that forms on the
polyps and swallow the microorganisms and detritus trapped in it
(Kuhlmann, 1985). Still others can directly absorb nutrients
(ammonium, nitrate and phosphate used by the zooxanthellae as well as
various amino acids) from the water (Franzisket, 1974; Muscatine and
Porter, 1977; D'Elia, 1978; Muscatine and D'Elia, 1978).
Ok what I am trying to show you Brucey, is through decades of scientific study (not folks making money off the hobby) it has been proved that almost everything we keep in our tanks feeds on detritus/waste/food/organics and all the things that associated with them (ie: bateria/nekton/larvae and so on). You as with me have an abundance of these items in our tanks, in most cases to much and we are looking for a way to remove them. If we allow them to be available to our critters and then remove the excess, we dont allow the balance to create a problem. If we have all this stuff and we continue to add more stuff to feed the corals and such directly we are making it so the corals dont need the above as thier stuffed already and thus we have more of an export issue to deal with.
Natural foods are enlarge far less nutritional then simple prepared fresh seafood. Natural food sources such as larvae/rotifers/copapods/ampapods and so on are comprised of more then just the nutrition the critters need. they have shells/antenii/legs and so on, which do not have nutritional value (or very very little). now compared to fresh seafood which is all meat and thus nutrition. Feed your fish and the extra and waste products will feed the balance of the critters in your system. If you have a coral or anenome that requires more food then it can get through this, then just directly feed it a little bit of the food you were feeding the fish.
 

Gina

Well-known member
Joined
Mar 6, 2004
Messages
54
Location
Maryland
Mike,
I read your above post and I do have one question. We have a Tubastrea (tube coral) and were told that we had to feed it by hand, which we have been doing. Do you think this is really neccessary or is it catching microorganisms and detritus at night when the polyps are out?
 

Montanarocknreefer

New Sheriff In Town
Joined
Jul 21, 2003
Messages
467
Location
Missoula, Montana
Hey Mike!

Magoo here!:D

I understand the fact that with a sand bed we have critters that stir up the bed thus allowing food particles and detritus to reach corals by way of water flow and have always thought sand storms in a tank were good.

Now with my new system which will be BB this will not be the case for the most part. There will be alot of water flow in this tank so assuming I will have to close down the flow to feed or will it be necessary?

I have always liked my home made "mush" for feeding and know this to be very potent and feed about twice or three times a week. As you say the faster we rid the tank of detritus the better we are.

Hope to have mostly a sps/clam dominated tank with 2-4 small fish to give the appearance of a bigger reef.

Thanks for sharing the information with us Mike!:)
 

Ritz

Member
Joined
Mar 16, 2004
Messages
13
Location
Anytown, U.S.A.
Gina, it can't hurt to feed the tubastrea by hand. It ensures that it is getting fed.

you can always go with a feeding dome. I've seen tubastreas open up under bright halides when food is introduced to the tank. takes some time to get em to switch to the light side.
 

mojoreef

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Messages
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Location
Sumner
Gina tubastrea is the coral with no zoox algae, thus it relies purely on the capture of food and/or direct absorption through its tissue. So the above pertains but because it has no internal source of food generation. Its ability to capture food is critical. As a Ritz said direct feeding of this is usually required. This particular coral is one of those anomalies.

I understand the fact that with a sand bed we have critters that stir up the bed thus allowing food particles and detritus to reach corals by way of water flow and have always thought sand storms in a tank were good.
John yes and no. When the food particles, detritus, other organics are suspended in the water column. They are very available for capture or used by corals. And in the wild, that is their main source of food. As per critters in the sand, stirring it to a point to where it is resuspended that does not happen. The movement of these critters is neither fast enough or violent enough to resuspended the particles. Couple that with the biofilm formed by bacteria in and around all surfaces of the sand and it's just not going to happen through the movement of a critter that lives in the sand.
Now with my new system which will be BB this will not be the case for the most part. There will be alot of water flow in this tank so assuming I will have to close down the flow to feed or will it be necessary?
John with a tank that has a deep sand bed or really any kind of sand substrate. The food that falls out of the water column and lands on it is food for the sand bed, and will not be available for corals. When waste/detritus/food lands on the sand substrate bacteria quickly envelop its with reducing enzymes and bind it to the bed. Once there, it becomes food for all that lives in the bed. With a tank with no sand substrate, well positioned water flow keeps the food/detritus resuspended and continuously in the water column where it is once again available to those that may need it. Eventually, the food/detritus exits the tank through the overflow system and is removed. Which I believe to be a lot better than to allow it to sit in the tank and rot away. On my system I do not turn off any pumps when feeding, remember its not so much the extra food that feeds the coral as it is the waste from the fish and other higher lifeforms in the tank.

A good general rule when looking at how much external food a coral requires is to look at the amount of tissue the coral has. The main use of nitrogen and phosphates in corals is for the production and building of its tissue. Here's an example: an SPS type coral has only a very thin veneer of tissue over a calcerious skeleton, thus its need for external amounts of nitrogen and phosphate food types is very low. And opposite example would be the say a torch coral. A torch coral has considerably more tissue and thus it requires more external food sources, but it is also highly developed in the capture of such food and can cover a lot more area of the water column. So just in the nature of it it will capture more food/detritus/organics if they are left suspended in the water column.
 

Ritz

Member
Joined
Mar 16, 2004
Messages
13
Location
Anytown, U.S.A.
I would imagine that feeding the tank about an hour before lights out might leave some food in the water for the tubastrea but you really need to ensure that they receive food.

Such a beautiful coral and such a pain in the butt.

and please Mojo, call me crak.
 

Gina

Well-known member
Joined
Mar 6, 2004
Messages
54
Location
Maryland
We have been feeding our tubastrea by hand. It does seem to know when the food is coming! All the polyps come out as to say feed me! All good info Miike!! Thank you very much. I have a headache now! LOL j/k!!!

Good to know the answer re: the BB issue!

P.S. I will agree 100% it is a pain in the butt! But, oh the beauty!
Wish they were out all the time!
 

jks1

Well-known member
Joined
Nov 29, 2003
Messages
179
Mike, great post. So I assume that all of the more "fleshy" corals in particular LPS will benefit from direct feeding. Is it necessary to feed them once a day or couple times a week? I am thinkning in particular about an open brain.
 

NaH2O

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Jan 25, 2004
Messages
8,568
So I assume that all of the more "fleshy" corals in particular LPS will benefit from direct feeding
IMO, they will benefit somewhat (and this would vary from species to species and their ability to capture - which takes energy) - don't forget when you feed the tank they will get some of the excess not to mention the fish waste. Not only LPS, but corals that don't rely on symbionic algae for food would get benefit from direct feeding. Someone correct me if I don't have a good understanding here.

As far as an open brain goes....I think it depends on each coral and how much of the excess food and fish waste it is taking in. I don't believe there is a set requirement....I do know that some feed their's a couple of times a week, but I'm not sure of particle size (which is also important).

Here is another thread on the subject: Let's Talk About It ~Coral Feeding~
 

mojoreef

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So I assume that all of the more "fleshy" corals in particular LPS will benefit from direct feeding.
well John to be honest I would'nt really say that. Most all corals feed in minute amounts constantly through the day when they require nutrition. Now this constant feeding is not just through capturing food but also through nutrient absorption through their tissue. I think target feeding in most cases can pose problems with food just landing and sitting on the coral. Which could eventually lead to a bacterial infection. If you take the fact that most fish feed constantly through the day and poop constantly through the day this usually gives the corals that constant influx of the nutrition they made toppled with direct absorption. Of all the corals I have ever capped the Tubastrea is the only coral that I have ever directly fed. I have a torch coral with over 60 heads and about the size of a basketball that has never seen a drop of food directly fed.
You really need to pay attention to the coral. Start off with feeding by feeding nothing then monitor the coral for for the results of that. Here is how I kind of approach it. If I have an open brain style coral in my tank. I place it in an area with softer flow so detritus/waste naturally gathers. I will not feed it directly whatsoever. I will keep an eye on the tissue mass of the brain. If I see it not growing I will increase the feeding of the fish slightly, this should directly benefit the brain through the production of more detritus/waste. If it still does not help the brain that I will consider a very small amount of direct feeding, although in 18 years of keeping corals this is never happen.
What one always has to keep in the back of their mind in regards to feeding corals and your tank. Is that overfeeding can be an absolute killer of your system. So always make the addition of food a last resort or at least very begrudging.

Crak corals feed as a result of mechanical and chemical responses to their environment. In the wild they adapt to how the environment offers these responses. In a closed system they will also respond the exact same way, if good flow is keeping the detritus/food/waste in the water column and available for the corals they will be in a constant state of stimulus and/or will simply gather food when they require it. Remember gathering in solid foods for a coral is a high energy demand process. Direct absorption is far less, and the internal symbiotic feeding relationship between the corals algae and itself is by far the least amount of energy a coral needs to use in order to feed itself. Less energy spent on feeding allows for a higher energy budget for neat stuff like growth.

Mike
 

NaH2O

Well-known member
Joined
Jan 25, 2004
Messages
8,568
Great info! It has been difficult to get past all the misinformation I have read on feeding corals and their requirements for supplemental food sources. I was going to ask about a tank that has a low fish load - but you pretty much answered that with this statement:
I will keep an eye on the tissue mass of the brain. If I see it not growing I will increase the feeding of the fish slightly, this should directly benefit the brain through the production of more detritus/waste. If it still does not help the brain that I will consider a very small amount of direct feeding
And here is the picture that goes along with this:
I have a torch coral with over 60 heads and about the size of a basketball that has never seen a drop of food directly fed.
 

jks1

Well-known member
Joined
Nov 29, 2003
Messages
179
man I love that torch..

guess you just have to find that happy medium between under-feeding and adding too much causing excess nutrient/phos.

Thanks for the great info!
 
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