What Happens When A Coral Isn't Fed

[Dana Riddle]

A small Porites (3" diameter) was placed in a 240-gallon holding tank with only two small fishes (that were fed once daily.) Lighting and water motion were monitored and considered to be sufficient. In retrospect, I should have monitored nutrient content as well but the gist of this procedure was to monitor what happens when a coral is transferred from one tank to another with different lighting. Chlorophyll content of zooxanthellae was made through use of an Opti-Sciences chlorophyll meter at 8 points on the coral over the course of about 2 months. The coral initially did well but soon did not have polyp expansion and began to lose color. The chart shows an initial increase in chlorophyll content, perhaps due to the coral being underfed and beginning to consume its own tissues in order to survive. After about two months, the chlorophyll content was reduced by 93%. Unfortunately the coral eventually died. I am sharing this information only in the hopes that some good will come out of its loss. I think the message here is 'feed your corals.' For obvious reasons, I do not want to repeat this experiment. Had I know the coral would die, I would have abandoned the procedure.

 

[homer1475]

Don't corals with the proper lighting get 99% of their daily nutrition from the zooxanthelle(sp?) to begin with?

I've honestly only ever fed my corals fish poop, light, and maybe once a week if I remember some broadcast feedings with LRS and PE mysis(I might do this once a month since I always forget), and mine seem to be doing fine.

 

[Dana Riddle]

Don't corals with the proper lighting get 99% of their daily nutrition from the zooxanthelle(sp?) to begin with?

I've honestly only ever fed my corals fish poop, light, and maybe once a week if I remember some broadcast feedings with LRS and PE mysis(I might do this once a month since I always forget), and mine seem to be doing fine.

They can get most of their required carbon but insufficient nitrogen will cause zoox starvation. You are feeding your corals with fish poop. Two small fishes in this 240-gallon tank was not sufficient to feed the coral IMO.

 

[dave57]

A small Porites (3" diameter) was placed in a 240-gallon holding tank with only two small fishes (that were fed once daily.) Lighting and water motion were monitored and considered to be sufficient. In retrospect, I should have monitored nutrient content as well but the gist of this procedure was to monitor what happens when a coral is transferred from one tank to another with different lighting. Chlorophyll content of zooxanthellae was made through use of an Opti-Sciences chlorophyll meter at 8 points on the coral over the course of about 2 months. The coral initially did well but soon did not have polyp expansion and began to lose color. The chart shows an initial increase in chlorophyll content, perhaps due to the coral being underfed and beginning to consume its own tissues in order to survive. After about two months, the chlorophyll content was reduced by 93%. Unfortunately the coral eventually died. I am sharing this information only in the hopes that some good will come out of its loss. I think the message here is 'feed your corals.' For obvious reasons, I do not want to repeat this experiment. Had I know the coral would die, I would have abandoned the procedure.

I’ve always thought about the effects of feeding sps every night vs once a week. I’m gonna have to try this out and see what happens over the span of 1 month or so.. do you have any experiences with feeding sps daily?

 

[Dana Riddle]

I’ve always thought about the effects of feeding sps every night vs once a week. I’m gonna have to try this out and see what happens over the span of 1 month or so.. do you have any experiences with feeding sps daily?

Yes, I feed my corals daily. I feed the fishes a cube or two of frozen mysis daily. These cubes are thawed in green water I culture, and to this I add a drop of an amino acid supplement, a tiny pinch of yeast, as well as an engineered coral food. This feeds the corals directly. Various zooplankton also feed on some of this food and are eaten by the corals. Nutrient control is important when using this method - a skimmer runs at might to export uneaten microalgae (current levels: NO3-N = 0.5 ppm and Phosphorus as P = 0.05 ppm.)

 

[dave57]

Yes, I feed my corals daily. I feed the fishes a cube or two of frozen mysis daily. These cubes are thawed in green water I culture, and to this I add a drop of an amino acid supplement, a tiny pinch of yeast, as well as an engineered coral food. This feeds the corals directly. Various zooplankton also feed on some of this food and are eaten by the corals. Nutrient control is important when using this method - a skimmer runs at might to export uneaten microalgae (current levels: NO3-N = 0.5 ppm and Phosphorus as P = 0.05 ppm.)

This is awesome, I’m going to give it a shot! Thank you Dana for your input. I had to start dosing nitrates due to my system gobbling up nutrients like it’s a sponge, I have a cheato refugium that drinks the nitrates and phosphates... the amount I feed is probably a quarter size of LRS fish frenzy and couple pinches of NLS pellets with a small amount of nori daily. My tank is 100 gallons with about 10 fish.. my nutrients no3 barely visible on the nitrate test (Redsea) and phosphorous 6 ppb (0.016 ppm) on the Hanna ULR. Coral colors are vibrant but growth is slow.

 

[ink]

Hello Dana, my experience seems to be the opposite of most aquarists and I struggle understanding why.
I am an acropora fan, but in the last years I feel I can't feed anything in my tank.
My actual system is 1200 liters, I have 3 fishes (2 tangs and 1 neocirrithes, about 27cm total lenght) that are healthy, with large tummies, despite I have not fed my tank for months. I have a macroalgae refugium that is thriving (mostly caulerpa and chaetomorpha, but also some bryopsis). I follow triton method.
In DT, I previously I had bryopsis issue, now they have reduced.
Previous triton NDOC test (at the moment bryopsis was diffused along the DT), TBN was 0,6mg/l and had zero nitrate with salifert test kit.
My acroporas are all dark brown and have small to no growth. Triton ICP test finds all tested elements are at the optimal level.
My experience showed me that any kind of food I add (from granular or flake food to fishes, or solution or powder products specific for corals) causes signs of harms, ranging from reduced polyp expansion to STN/RTN, and appearance of cyanobacteria, quick growth of bryopsis and appearance of mucus/slime on rocks and over macroalgae, that seems to worsen health/growth.
In my experience (about 20 years, but a bit more reliable and scientific in the method only in the last 10 years), I've never experience steady nitrate detection. I tried reducing light, skimming, increasing feed regimen, but all I got was darkening and worsening of SPS till their death, w/o detecting steadily some nitrate (sometimes temporarily found 0,2ppm).
I sincerely struggle to understand how is it possible that most aquarists, also keeping sensitive SPS, feed and detect nitrate (1-5ppm) and experience good growth. I instead find hard to keep acroporas (actually more then in the past) even without feeding and feels to harm them when I feed any organisms in the system. And without feeding, macroalgae grows and fishes are perfectly healthy.
I tested multiple salifert nitrate test kit vs knowkn concentration of nitrate and find it enough accurate for my purpose. RO water is ICP tested and have always much care to keep 0,00 uS. I don't do regular water changes, as per triton method, but tried in the past to make some using twolittlefishies accurasea1 salt and red sea classic, that have shown to have the smallest quantity of contaminants and have no difference among batches.

Thanks for your attention.

Luca

 

[EMeyer]

Don't corals with the proper lighting get 99% of their daily nutrition from the zooxanthelle(sp?) to begin with?

I've honestly only ever fed my corals fish poop, light, and maybe once a week if I remember some broadcast feedings with LRS and PE mysis(I might do this once a month since I always forget), and mine seem to be doing fine.

The 99% number is correct but the details are often misquoted. Its "Photosynthetically fixed carbon from the symbionts can supply up to 99% of the coral's energy requirements".

"Can" and "up to" are important qualifiers.

Further, the symbiont only donates carbon (in the form of sugars or glycerol); the coral still has to get its N and P from somewhere.

Personally, I suspect the lack of 24-7 live zooplankton food is one of the biggest challenges for corals in captivity.... we can match most other aspects of the environment but that one.

 

[Dana Riddle]

Hello Dana, my experience seems to be the opposite of most aquarists and I struggle understanding why.
I am an acropora fan, but in the last years I feel I can't feed anything in my tank.
My actual system is 1200 liters, I have 3 fishes (2 tangs and 1 neocirrithes, about 27cm total lenght) that are healthy, with large tummies, despite I have not fed my tank for months. I have a macroalgae refugium that is thriving (mostly caulerpa and chaetomorpha, but also some bryopsis). I follow triton method.
In DT, I previously I had bryopsis issue, now they have reduced.
Previous triton NDOC test (at the moment bryopsis was diffused along the DT), TBN was 0,6mg/l and had zero nitrate with salifert test kit.
My acroporas are all dark brown and have small to no growth. Triton ICP test finds all tested elements are at the optimal level.
My experience showed me that any kind of food I add (from granular or flake food to fishes, or solution or powder products specific for corals) causes signs of harms, ranging from reduced polyp expansion to STN/RTN, and appearance of cyanobacteria, quick growth of bryopsis and appearance of mucus/slime on rocks and over macroalgae, that seems to worsen health/growth.
In my experience (about 20 years, but a bit more reliable and scientific in the method only in the last 10 years), I've never experience steady nitrate detection. I tried reducing light, skimming, increasing feed regimen, but all I got was darkening and worsening of SPS till their death, w/o detecting steadily some nitrate (sometimes temporarily found 0,2ppm).
I sincerely struggle to understand how is it possible that most aquarists, also keeping sensitive SPS, feed and detect nitrate (1-5ppm) and experience good growth. I instead find hard to keep acroporas (actually more then in the past) even without feeding and feels to harm them when I feed any organisms in the system. And without feeding, macroalgae grows and fishes are perfectly healthy.
I tested multiple salifert nitrate test kit vs knowkn concentration of nitrate and find it enough accurate for my purpose. RO water is ICP tested and have always much care to keep 0,00 uS. I don't do regular water changes, as per triton method, but tried in the past to make some using twolittlefishies accurasea1 salt and red sea classic, that have shown to have the smallest quantity of contaminants and have no difference among batches.

Thanks for your attention.

Luca

Hi Luca,
I'm not all that familiar with the Triton method. I understand that NDOC shows the C/N/P ratios. What is TBN?
If I did my math correctly, your tank holds 300 US gallons, and total length of fishes is about 11 inches.
Were the corals ever colorful?
Just off the top of my head, it sounds like the corals are starving.

 

[madweazl]

This tank gets LRS Reef Frenzy twice a day, algae sheets occasionally (I forget to toss it in there most days but still happens at least once a week I'm ashamed to say), and 2-part. 15-20 gallons of water is changed weekly. Nitrates are typically <.5ppm and phosphates typically hover around .1ppm; I feed the fish quite a bit. Nothing else enters this tank; I don't want people to confuse "feeding" with the direct application of food to the corals (aminos, reef roids, or any other similar products). Other corals may require additional food but acroporas do not in my experience (nor monti caps, undatas, turbinaria, or leptos). Oh, there is some cyphastrea and tubipora I've been trying to kill and cant.

 

[ink]

Hi Luca,
I'm not all that familiar with the Triton method. I understand that NDOC shows the C/N/P ratios. What is TBN?
If I did my math correctly, your tank holds 300 US gallons, and total length of fishes is about 11 inches.
Were the corals ever colorful?
Just off the top of my head, it sounds like the corals are starving.

Hi Dana, system volume is correct (317 gal).
Triton method is based on macroalgae refugium and skimmer, no water changes and replacement of consumed elements with balanced solution and regular ICP-OES water testing in order to correct low or high elements concentration.
NDOC test measures total organic and inorganic carbon and total nitrogen bound (TNb, sorry, not TBN). They suggest to have NO3 being 2/3 of all total nitrogen. And TNb 0,4mg/l.

I think my nutrients were high because skimmate was abundant, algae and cyano were growing quickly, TNb was high (0,6mg/l) with no NO3 (maybe all ammonia?).
In the last 2 months I have not added any food (nothing) and skimmate progressively reduced. Cyano and slime over macroalgae disappeared, hairy algae reduced and macros improved. Corals slightly improved, but very small growth.
Yesterday, after my previous message, I found for the first time macros in the refugium were dying and valonia in DT was doing the same.
I am now trying adding a small amount of food and a product by triton made of NO3 and PO4 and will look what happens. But In the last couple of years every time I added food, corals worsened, and even died. Their colors and health has been unstable, with really low or none growth. I suspect this dealt with live rocks, maybe they were low quality and rich in organic matter to be decomposed and this took lot of time. Maybe any added food worsened an environment were there was already too much organic nitrogen being decomposed into ammonia. I don't know if excess ammonia was the issued or excess of bacteria, but I'm quite confident that until now, feeding meant to harm.

Anyway, also in my others tanks in the past, I've never been able to keep SPS alive and growing with nitrate more than barely detectable.

Luca

 

[Daniel@R2R]

Very interesting discussion! Following!

 

[Dana Riddle]

We shouldn't forget a bacterial imbalance in an aquarium. Hope to have a DNA analysis of bacterial populations in my aquarium soon. This could be as important as a Triton (or other) ICP analysis.

 

[blstravler]

This tank gets LRS Reef Frenzy twice a day, algae sheets occasionally (I forget to toss it in there most days but still happens at least once a week I'm ashamed to say), and 2-part. 15-20 gallons of water is changed weekly. Nitrates are typically <.5ppm and phosphates typically hover around .1ppm; I feed the fish quite a bit. Nothing else enters this tank; I don't want people to confuse "feeding" with the direct application of food to the corals (aminos, reef roids, or any other similar products). Other corals may require additional food but acroporas do not in my experience (nor monti caps, undatas, turbinaria, or leptos). Oh, there is some cyphastrea and tubipora I've been trying to kill and cant.

I just changed to LRS - only once a day - creates a storm in my tank and everyone gets some including the coral. I still feed Phyto Feast from Reef Nutrition at night along with a few drops of amino acids.

 

[Sharis100]

Always feed our corals

 

[GJak]

Hello Dana, my experience seems to be the opposite of most aquarists and I struggle understanding why.
I am an acropora fan, but in the last years I feel I can't feed anything in my tank.
My actual system is 1200 liters, I have 3 fishes (2 tangs and 1 neocirrithes, about 27cm total lenght) that are healthy, with large tummies, despite I have not fed my tank for months. I have a macroalgae refugium that is thriving (mostly caulerpa and chaetomorpha, but also some bryopsis). I follow triton method.
In DT, I previously I had bryopsis issue, now they have reduced.
Previous triton NDOC test (at the moment bryopsis was diffused along the DT), TBN was 0,6mg/l and had zero nitrate with salifert test kit.
My acroporas are all dark brown and have small to no growth. Triton ICP test finds all tested elements are at the optimal level.
My experience showed me that any kind of food I add (from granular or flake food to fishes, or solution or powder products specific for corals) causes signs of harms, ranging from reduced polyp expansion to STN/RTN, and appearance of cyanobacteria, quick growth of bryopsis and appearance of mucus/slime on rocks and over macroalgae, that seems to worsen health/growth.
In my experience (about 20 years, but a bit more reliable and scientific in the method only in the last 10 years), I've never experience steady nitrate detection. I tried reducing light, skimming, increasing feed regimen, but all I got was darkening and worsening of SPS till their death, w/o detecting steadily some nitrate (sometimes temporarily found 0,2ppm).
I sincerely struggle to understand how is it possible that most aquarists, also keeping sensitive SPS, feed and detect nitrate (1-5ppm) and experience good growth. I instead find hard to keep acroporas (actually more then in the past) even without feeding and feels to harm them when I feed any organisms in the system. And without feeding, macroalgae grows and fishes are perfectly healthy.
I tested multiple salifert nitrate test kit vs knowkn concentration of nitrate and find it enough accurate for my purpose. RO water is ICP tested and have always much care to keep 0,00 uS. I don't do regular water changes, as per triton method, but tried in the past to make some using twolittlefishies accurasea1 salt and red sea classic, that have shown to have the smallest quantity of contaminants and have no difference among batches.

Thanks for your attention.

Luca

What is your phosphate at? Sounds like that may be the culprit based on your description.

 

[Ben Pedersen]

Last year there was research published identifying a direct link between the success of reef corals (hard and soft) with the number of fish on the reef. The research showed that the fish were constantly dosing the reef with waste feeding the coral which caused the coral to thrive attracting more fish. The research identified the ratio of fish required for a successful growing reef. The more fish, the more successful the reef. Without this high population of fish the reef would decline.

Coral needs food to thrive! I feed my coral and fish 4 times a day with an auto feeder. I feed half a nori sheet daily. I also feed a cube of frozen mysis twice to three times a week. I have way to many fish and my coral thrives. I skim, I top off with kalc water mixed with vinegar and have a refugium. I use phosgard.

I don't think people understand the need coral have of food and fish.

 

[Gareth elliott]

Hi Dana, system volume is correct (317 gal).
Triton method is based on macroalgae refugium and skimmer, no water changes and replacement of consumed elements with balanced solution and regular ICP-OES water testing in order to correct low or high elements concentration.
NDOC test measures total organic and inorganic carbon and total nitrogen bound (TNb, sorry, not TBN). They suggest to have NO3 being 2/3 of all total nitrogen. And TNb 0,4mg/l.

I think my nutrients were high because skimmate was abundant, algae and cyano were growing quickly, TNb was high (0,6mg/l) with no NO3 (maybe all ammonia?).
In the last 2 months I have not added any food (nothing) and skimmate progressively reduced. Cyano and slime over macroalgae disappeared, hairy algae reduced and macros improved. Corals slightly improved, but very small growth.
Yesterday, after my previous message, I found for the first time macros in the refugium were dying and valonia in DT was doing the same.
I am now trying adding a small amount of food and a product by triton made of NO3 and PO4 and will look what happens. But In the last couple of years every time I added food, corals worsened, and even died. Their colors and health has been unstable, with really low or none growth. I suspect this dealt with live rocks, maybe they were low quality and rich in organic matter to be decomposed and this took lot of time. Maybe any added food worsened an environment were there was already too much organic nitrogen being decomposed into ammonia. I don't know if excess ammonia was the issued or excess of bacteria, but I'm quite confident that until now, feeding meant to harm.

Anyway, also in my others tanks in the past, I've never been able to keep SPS alive and growing with nitrate more than barely detectable.

Luca

With the ndoc report do they give you guidance like their icp testing? Curious as to what they recommend to get to their magical 2/3 ratio. Also how they achieved this ratio, most studies i have read point that no4 is preferred over no3 in most aquatic photosynthetic organisms. In fact in tanks with large coral or plant biomass tanks , it is common to test very low no3 as most no4 is used before conversion occurs. Perhaps i am over thinking it

 

[Kyl]

When my nitrates become undetectable my SPS always suffer. It's been that way through the almost two years my DT and frag tanks have been running, and the two years of nanos previous to that. Anecdotally the behavior matches what I see, polyp extension starts to wane then the colour pigment begins to fade. Some pieces this results in loss, others recover over a few months as nitrate levels are maintained via KNO3 additions and reefroids regularly.

Interesting to read some of the potential science behind this behavior result.

 

[shred5]

I have always believed feeding our corals is better..
They can get allot of their nitrogen, phosphorus, carbon, amino acids etc from food.

People sit there and get pail colored corals and start dumping nitrogen and phosphorus in the water. People have got so afraid of everything like a little algae there tanks have got too sterile.

As far as fish poo I wonder how much really gets to a coral or how many actually can or will eat it.