Feeding corals

[pnikiel]

I got some great advise in one of the other forums on this site in regards to feeding my fish. In getting this someone also suggested that I was probably wasting my money and poluting my water feeding a pre-packaged liquid phyto product to the corals. He suggested that fish waste was probably enough to keep the corals happy.

I'm all for saving the $$$ and keeping the water clean. Does anyone else want to weigh in on this? It's an interesting thought.

 

[Krish]

Yeah...Some corals use fish poop and detritus as food. That's why you hear alot of talk about good flow for keeping detritus lifted off of the rock in suspension so for one, the corals can use it up. There are other reasons for keeping detritus in suspension, but coral feeding is one. HTH

 

[Curtswearing]

Very few corals eat phytoplankton.

They eat Dissolved Organic Materials, bacterioplankton, zooplankton, and most off of photosynthesis as well.

 

[c0yote]

If you want to supplement, I believe you feed phytoplankton to sponges, tubworms, etc. and zooplankton to corals.

 

[NaH2O]

pnikiel - what types of corals do you have?

 

[pnikiel]

I'm just starting my collection (had gone "fish only" for three years) so it isn't much. I have a decent sized open brain coral, some frog spawn, some button polyps, a few small mushrooms and I'm trying to resurect a nearly gone bubble coral. And a friend just gave me a small shel with some zenia on it that I'd like to propogate.

Hoping to try others...

 

[pnikiel]

So I'm still trying to get this straight. Is the concensious that most corals don't need to be fed? That they'll do fine with good light, good water movement, and good fish poop?

Sounds too good to be true!

 

[DonW]

So I'm still trying to get this straight. Is the concensious that most corals don't need to be fed? That they'll do fine with good light, good water movement, and good fish poop?

Sounds too good to be true!

Its really nothing new. Just do a little research

Don

 

[jezzeaepi]

No coral gets 100% of its energy needs through light. Most corals eat zooplankton though not phyto(although i think gorgonians and a few other soft corals eat phyto). Some corals will readily except food, and Im sure they will grow much quicker with target feeding. Other corals seem to not except food at all, and for those I just let them grab whatever is in the water column from feeding the fish.

 

[albert]

According to J. Sprung all the common corals used in aquarium hobby, except one genus (Millepora), do eat phyto.

Source:
Julian Sprung (1999). Corals. A Quick Reference Guide. Ricordea Publishing, pp. 240

 

[Curtswearing]

According to J. Sprung all the common corals used in aquarium hobby, except one genus (Millepora), do eat phyto.
Source:
Julian Sprung (1999). Corals. A Quick Reference Guide. Ricordea Publishing, pp. 240

I don't have that book so I'm not sure how he wrote it but I suspect you're accidentally misreading it (or Julian is sadly mistaken). It's common knowledge that phytoplankton is a HUGE food source near the bottom of the food web. However, it is not DIRECTLY ingested by MOST corals. They've found live phyto in the gut of a few corals but they have not found partially digested phyto in almost all others.

 

[albert]

I don't have that book so I'm not sure how he wrote it but I suspect you're accidentally misreading it (or Julian is sadly mistaken).

The book is good in the sense that it's quite impossible to misread it, almost no text to read, pictures and pictograms only.

It's common knowledge that phytoplankton is a HUGE food source near the bottom of the food web. However, it is not DIRECTLY ingested by MOST corals. They've found live phyto in the gut of a few corals but they have not found partially digested phyto in almost all others.

That's exactly I used to know, e.g. from Wetwebmedia :lol:

Pearl bubble
Hello to you all,
<Hellooooooo Helene!>
I have read all over the WWM site and still can't seem to figure out what to do for my Pearl Bubble.
<flowers, soft music and candlelight always make me feel better. That and a fifth of brandy. Do consider... for the coral, that is... not for me. I can take care of myself>
All seems well in the kingdom for the all other life but the pearl just keeps on shrinking...
<do you play Mariah Carey a lot?>
I have been trying to tempt him to eat with a little direct feeding of zooplankton and phytoplankton mixture.
<good with the zoo... but don't waste your time on the phyto with this species. Form follows function, and this coral has huge feeding tentacles designed to catch large zooplankton. No plant matter here>...
<best regards, my friend. Anthony>

And now, let's have a look to the Bubble coral from the book, note the phyto symbol (second from the left).

 

[Curtswearing]

LOL!!!

Leave to you Albert to take a picture of the book for us. (BTW, this is off topic but what kind of camera do you have? Your pic's are always stunning).

As much as I enjoyed speaking with Julian at length about flowerpot corals numerous IMAC's ago, I'm going to go out on a limb here and say that Julian IS COMPLETELY WRONG. Very few corals have the ability to "clear the phyto" according to testing. Beyond that, of the species that did "clear the phyto", it is typically found undigested in the coral's gut in almost all species.

While some studies have indicated that some stony corals are capable of clearing phytoplankton from the water, these experiments have not been rigorous (Wilkinson et al. 1988, Szmant-Froelich and Pilson 1984, Sorokin 1981, 1995). Ingestion does not equate to digestion. The extent to which phytoplankton contribute to stony coral nutrition is unknown, but it is probably unlikely that phytoplankton are an important food source for most stony corals. Among those reported or suggested to clear or ingest phytoplankton are: Acropora, Siderastrea, Montipora, Porites, Astrangia and Tubastraea. Other studies tend to directly refute these suggestions for all but Astrangia and Porites. More directly, Goniopora and Alveopora may have more herbivorous tendencies (Peach unpublished thesis). Stony corals are generally not well adapted to the sieve or filter type feeding that characterizes the soft corals (Fabricius et al. 1995, 1998). They are, however, well suited to the capture of zooplankton prey. I am sure that future studies will examine potential roles of phytoplanktivory in the Scleractinia in more detail. However, I think it safe to assume that the number of stony corals that depend on phytoplankton as a food source will be minimal, or that the relative contribution of phytoplankton to their energy needs will be slight.

http://www.reefkeeping.com/issues/2002-10/eb/index.php

The suggestion that phyto is DIRECTLY used by MOST corals goes against the work done by;

Yuri Sorokin (Who I think is a genius)
C.M. Yonge
Howard T Odum (Veeeery unusual individual if you read his books)
Countless others

It is scientific fact that many azooxanthellae corals ingest phyto. Several octocorals (particularly sea whips, sea fans, and sea rods) heavily rely on it and it is suspected that goniopora and alveopora do as well.

Beyond all of the science....I've seen too many tanks grow and thrive without any addition of phyto for me to believe that most corals utilize it. With the exception of my prop tank, I alway generated some internal phyto by just magnet cleaning my glass. Some of my corals reacted to this magnet cleaning but I could put a drop of my blood into my tank if I wanted to and I would get the same reaction.

Basically, I don't see the need to add phyto unless you have baby clams, azooxanthellate corals, or decorative featherdusters and sponges.

 

[MarineTeng]

well to get back on topic, i could tell no grow difference from the short time i used phyto and when i don't, so i don't now, as your tank matures it'll just feed the corals with all the random stuff that grows

 

[NaH2O]

Here is a past thread mojoreef did:

Let's Talk About ~Coral Feeding~

Here are a few quotes from different sources:

From: Coral Reef Ecology by Yuri I. Sorokin, page 347-348

The composition of animal food, ingested by corals in situ has been studied by Porter (1974b). He extracted the gut contents of the coral Montastrea annularis in situ with the aid of a syringe. The extracted material contained copepods, ostracods, mysids, chaetognaths, appendiculariuns, nematods, polychaetes, small jelly fish and salps. The dominating components in the gut contents were zoea and copepods. The suspended organic material ingested by corals in situ via sedimentary filtration included bacteria, protozoa, detritus, and dead zooplamkters (Lewis and Price 1975; Lewis 1976). Corals readily ingest also the faeces of fish (McCloskey and Chester 1971). As regards algae and other plant material, the scleractinian corals rejected them. Even if swallowed by the polyp, this material was not digested and was soon regurgitated (Yonge 1973; Sorokin 1973a).

Same book cited above, pages 355-356

Summarizing the data on the quantitative aspects of feeding of scleractinian corals obtained at the Heron Island reefs, it could be concluded that at the ambient concentration of available food they, on an average, could compose their energy balance as follows: 70% of the needed energy is supplied to them by the photosynthesis of their zooxanthellae, 20% by predation, and 20% by feeding on DOM and on bacterioplankton.

Same book, page 355 (Feeding of Zantharia, Antipatharia, Ceriantharia and Octocorals)

Data on the feeding of these groups of Anthozoa are still scarce. The zoantharians by the morphology of their polyps as well as by their symbiosis with zooxanthellae should be similar in this aspect to the scleractinians. In fact, a larger part of the necessary nutrition they get from their algal symbionts, using the other available sources of heterotrophic feeding: zooplankton, DOM, and bacterioplankton (Reimer 1970, 1971, 1972; Trench 1974; Sebens 1977). It seems that their different species may use the autotrophic source of nutrition to a different degree. Such common zoantharians as Zoanthus sociatus are primarily autotrophs, while the Palythoa are powerful predators, which may acquire a large portion of necessary energy and nutrients in this way.

page 359

In Xenia for example, Gohar did not find any signs of predatory feeding at all. The guts of Xenia were permanently empty. This alcyonacean did not even display any "food reaction" in the presence of food, which is a most important feature of feeding behavior in Scleractinia. As for the nutrition of another symbiotic octocoral, Clavularia, its polyps extruded periodically an excess of zooxanthellae into their gastral cavity, where these were digested and assimilated.

Here is a link to Non-Photosynthetic Corals: They are really hard! by Delbeek

The vast majority of soft corals and gorgonians available in the hobby rely greatly on zooxanthellae for their nutrition. However, recent studies have shown zooxanthellae may not be able to meet the total nutritional needs of all soft corals. Fabricius and Klumpp (1995) found that twelve of the most common photosynthetic soft coral species investigated on the Great Barrier Reef could not meet their carbon requirements by photosynthesis alone. This brings up the question of just where do they get their carbon? Many octocorals are known as polytrophic feeders, meaning that they are capable of obtaining nutrition from more than one source (Williams, 1993). Possible sources may be one or all of the following: the direct absorption of nutrients, the ingestion of zooplankton and/or phytoplankton, the ingestion of "marine snow" along with its attached bacteria and organic material. Several studies have shown that soft corals, gorgonians and sea pens can feed on a variety of zooplankton such as copepod nauplii and eggs, invertebrate eggs and other small items of poor mobility. Many of these studies, however, were conducted in the laboratory, using artificial foods (Artemia) or concentrated natural zooplankton of unknown density (Fabricius et al., 1995a). These studies showed that octocorals tend to be highly selective for non-evasive forms such as mollusc larvae; indicating poor capture ability of more elusive prey such as large adult copepods. This poor capture ability is most likely due to the lack of effective nematocysts, resulting in the selection of less motile prey (Fabricius et al., 1995a). In fact, Fabricius (unpublished data) found that an inability to feed on zooplankton was widespread amongst zooxanthellate soft coral genera on the Great Barrier Reef (i.e. three species of Sarcophyton, two species of Sinularia, Cladiella sp., Nephthea sp. and Paralemnalia sp.). The role that zooplankton play in the nutrition of photosynthetic octocorals is, as yet, unclear but new information is showing that they contribute only a small portion to the nutritional budget of many octocorals (Fabricius et al., 1995a and b). However, many of the studies that looked at a corals ability to feed on zooplankton often used Artemia nauplii as prey items under controlled situations. Artemia are rather large, and it may not be surprising given the small size and weak nematocysts of many soft corals, that they are not easily captured.

From: The Reef Aquarium, Volume Three, by Delbeek and Sprung, page 574

There is a seemingly endless variety of coral, with an equally bewildering array of polyp shapes and sizes that relate to the types of food they eat. Some corals have extremely narrow food size requirements based on their polyp size and structure, while others can feed on a wide variety of sizes. Some corals can feed on larger meaty foods (e.g. Catalaphyllia, Euphyllia, Trachyphyllia, Fungia), others feed on tiny zooplankton (e.g. Acropora, Seriatopora), while still others include large quantities of microscopic phytoplankton in their diets (e.g. Dendronephythya), and finally, some appear not to actively capture any prey at all (e.g. Xenia). It is therefore not surprising that what to feed corals in a reef aquarium has been the subject of much debate and speculation.

 

[MarineTeng]

just a thought about coral feeding, what if you cultured pods and then dumped a bunch in your tank at once, or targeted, would this work well?

 

[NaH2O]

There are types of reactors specifically for zooplankton. Something else to consider when thinking about getting food sources (other than light) to a coral if you choose to feed this way, is flow of the water. Not only getting food source to the coral, but for taking away wastes. Good flow would also aid in keeping detritus suspended for use, other wastes and the bacteria associated with it.

 

[Curtswearing]

Good Heaven's Nikki,

I'm going to FedEx you an icepack for your fingers. That's a LOT of typing. Thank you for taking the time to do it though.

just a thought about coral feeding, what if you cultured pods and then dumped a bunch in your tank at once, or targeted, would this work well?

In the Coral Feeding thread that Nikki linked to, it shows the advantages of blender-mush over natural feeding. Basically, there isn't a whole lot of wasted exoskeletons, antennae, etc. The seafood you put into your blender mush is 100% protein. You also cannot control the populations of live food.

Beyond that, the last link by Delbeek and Sprung indicates that most octocorals are very inefficient at prey capture. In addition, while SPS are more efficient at prey capture, they are highly particular on size of the prey.

While SPS do attack pods, they prefer bacterioplankton because the energy expenditure to get pods is so much greater.

Indeed, corals do actively feed on bacteria in the mucus, in the water, and attached to particulate matter. They typically utilize them for 5% of their diet, by weight. This is on an efficiency level on par with many of the specialized filter feeders and sponges. Sorokin found that, in general, bacterioplankton ingestion alone can provide from 8-25% of the coral’s respiratory demands. This amount is the equivlent of 1-10% of the animals total biomass per day...from bacterioplankton!! Its assimilation index by nutritional content is the equivalent to the nutrition acquired by the capture of small crustaceans (which are by weight, much greater and a greater energy expenditure to capture). Phosphorus, a normally limiting resource in coral reefs, is found in the cell walls of bacteria. Coral consumption of bacterioplankton provides them with a more easily assimilated source of phosphorous than from the uptake of inorganic phosphate contained in the water.

http://www.reefs.org/library/talklog/e_borneman_051098.html

 

[pnikiel]

Making your own "mush" makes sense, nutritionally. But I have to tell you... I'm already pushing it with my wife where it comes to this hobby. I can't begin to guess her response to my blending up raw seafood in our kitchen. (Who remembers the "Bass-o-Matic?)

So what about the prepared foods on the market? I tend to use the Ocean Nutrition cubes, Form.1, Form 2., some others. Would they have similar benefits to blender-mush?

(and I agree with the guy above... you're awesome Nikki.)

 

[NaH2O]

Curt did make a good point, which I didn't touch upon in my post, about energy expenditure. How much of the energy is given up vs. gained after capturing and digesting the shelled moving copepod? Compare that to the energy spent on taking in something like bacterial floc.

There is a food you can buy that is basically blender mush that you don't have to make (and it isn't gelled). I've found it much easier from a time standpoint to just buy it instead of blending it, plus when I consider purchasing all the items in the mix, it would come out about the same price. It is called Rod's Food, and I know Premium Aquatics carries it, but I'm not sure about other online retailers. You might want to look around a bit, and check our sponsors.

When I think of feeding corals in my tank, I blast the rocks to free up any excess detritus, and my flow is designed to keep detritus and wastes in suspension, which makes it easier to feed the critters that use it. What doesn't get used goes into the sump to be skimmed out. Anthony Calfo thought my corals were lacking a little food source (based on their coloration), and suggested I dose a little sodium nitrate (among other helpful tidbits). I added a decent sized purple tang to my tank recently, and I'm giving the extra waste load a chance to make a difference before I look into the sodium nitrate. So far, the Cyphastrea sp. has darkened up a bit, so we'll see what happens to the rest of the corals in the long run.