Sun Coral Feeding

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Guys, alot of people have asked me regarding feeding sun corals.

They are concerned at what would happen if not all heads are fed, as this is difficult most of the time, and one cannot always get to each head.

In very short, not all heads HAVE to eat... read further to see why...

I would like to post this from UltimateReef.com The author asked that I also put his name, Roger Hughes down as referrence together with Ultimate Reef.com

I have highlighted the most important aspects of feeding and the link to the website is at the bottom of the article...

Tubastraea Anatomy



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Images: Authors own



Corallite: The skeletal material produced by a single polyp
Calice (pl. calices): A concave depression the “end” of the corallite that houses the polyp
Septum (pl. speta): These are skeletal plates that radiate into the calice from the theca (the corallite wall). The Septum is also sometimes referred to as; scleroseptum
Coenosteum (pl. coenostea): The skeletal material between walls of adjacent corallites.
Coenosarc: The fleshy / skin type tissue covering coenostea and corallites.
Tentacle: A nematocyst-laden appendage used to capture prey, and also for defence / offence.
Oral disc: The broad area of tissue between the mouth and polyp tentacles.
Mouth: The mouth is a sphincter (ring of muscle) that open and closes to allow passage of food / waste to and from the Gastro Vascular cavity.
Gastro vascular cavity: The gut of the polyp.
Mesenterial filaments: The Gastro vascular cavity is divided into sections by these muscular “curtains” of tissue, which are used for digestion and polyp retraction / extension.


Feeding Methods and Handling

Due to the lack of Zooxanthellae, Tubastraea spp. MUST be fed by the aquarist between 2-7 times a week to maintain health and growth, for Tubastraea micrantha daily feeding is required. **This is not a coral for the lazy**. It is believed that each polyp must be individually fed on meaty offerings such as vitamin enriched brine / Mysis shrimp and krill along with other foods along the lines of, chopped mussel, squid, Cyclop-eze™, etc. It is believed that using live Brine shrimp as a part of the corals diet will increase the intensity of the coral colour, especially in the case of orange / yellow specimens.

When choosing a "sun coral" at a local fish shop, it is desirable to look for a specimen that is already feeding and shows little sign of starvation. A feeding specimen can be recognised as it will look puffed up or plump, especially after food is placed in the tank. Consider asking your local stockist to add some food to the corals holding tank, or ask what time they normally feed the coral, and if you can be present.

The tell-tale signs of an under-fed or malnourished animal are relatively easy to spot; such as clearly showing calices (cups), the coenosarc (flesh / skin) covering the cups will also appear to be extremely thin and taut. The presence of excessive algae growth may sometimes indicate a possible weakness. If your specimen already has algae present then every effort should be made to carefully remove the intrusion without causing damage.

After transportation and acclimatisation, a newly acquired sun coral may-be reluctant to expand its tentacles in preparation for feeding. These tentacles are used to capture and incapacitate prey which range in size from planktonic forms to small fish. One way of coaxing the polyps to expand and open, is to very gently waft / blow a small amount of brine shrimp juice, Phyto-plankton, Cyclop-eze™, or, Coral Vibrance™ over the cups of the coral.



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Images courtesy of: Steve Margetts



If, after several days and nights (sometimes a couple of weeks) of "wafting"the polyps still fail to show any sign of opening, its possible that the coral may no longer have sufficient energy remaining to expand, as a result the slow process of starvation will begin, along with tissue thinning and recession, eventually leading to death.


What is meant by, “sufficient energy remaining”? What the author is referring to is stored Nitrogen and Phosphorous within the coral skeletal body. In the absence of food the coral can use the ‘store’ to sustain life for a number of weeks if the coral was in good health prior to harvesting, etc. Unfortunately with some corals the process of actually getting to a reefers system is a drawn out stressful affair, and often goes without any food from harvest to purchase.

Interestingly, although it is commonly thought that each polyp of the colony is a separate animal, and as such do not share ingested nutrients, the ‘back-up energy’ supply is a common store held with in the porous skeleton for the good of the entire colony.

On a brighter note, it’s not all doom and gloom. Once Tubastraea is accepting your meaty offerings and the feeding regime is maintained, it’s a hardy inhabitant that will reward you with a daily stunning display of large, usually intensely coloured polyps, and in time daughter colonies within the aquarium (see, reproduction).

Once the coral is opening enough for you to feed, there are various methods of delivering food stuffs to the polyps that can be employed.

If the coral is to be fed within the aquarium, the simplest means is to use a syringe or turkey baster to deliver foods such as Mysis, and Artemia to the oral disc and tentacles of the polyp. Care must be taken during this process, if the food is released with to much pressure or the polyp is “poked”, it will contract and you’ll be unable to fed, until it re-expands.

When feeding within the aquarium, the food offered to the coral may be “stolen” by shrimps, who will actually remove the food from the gut of the coral. One method of combating this is to cover the coral will half a fizzy drinks bottle or similar, this is sometimes known as the “top hat” method. Another method of fending off unwanted visitors is to “guard” the coral with an acrylic rod; this method is preferred where the colonies are too large when expanded to be contained within the “top hat”.

An alternative method to feed this wonderful animal is to remove the coral from the aquaria in a suitably sized container. To carry out this procedure it is necessary to submerge the container, pick the coral up by its underside (scoop it up with an open hand) and place within the container, ensuring complete water coverage of the coral during removal always allowing for polyp expansion. Once the polyps have expanded, feeding can commence with your chosen foods. Once the coral has moved the food down to its gut, it may be returned to the aquarium by reversal of the above procedure. In the author’s opinion, this method should not be your first choice. Constant handling may cause stress and damage to the coral.

When handling the coral, great care must be taken as, although the main skeletal body is strong, the coenosarc, corallites and calices are fragile and easily damaged. Under no circumstances should the coral be removed from the water and exposed to the air if the polyps are extended. The result of such action can be torn tissue around the calice edge which, in some instances may be irreparable.

When feeding Tubastraea, it is important to remember that it is very easy to increase the NO3 (Nitrates), PO4 (Phosphates) and dissolved organics within the system due to the regurgitation of food (if it had eyes, they'd definitely be bigger than its belly), and food that "escapes" the polyps un-checked whilst feeding within the aquarium. There are many ways around this problem; ample detritus eaters or scavengers amongst the clean-up crew, heavy skimming and high flow, “algae scrubber” sumps, removing uneaten food, removing the coral for feeding (note: doesn’t help with regurgitation), regular water changes, and of course, only feeding little and often.

Tubastraea sp everything...3 - UltimateReef.com
 
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Guys I must however elaborate a bit on the feeding amounts per week...

If the coral is i excellent condition, twice a week will suffice, given that you supply it with at least live brine nauplii and Cyclop-Eeze. This is the only way a suncoral will survive twice a week feedings.

If you feed one cube of brine or squirt Zooplankton over it twice a week, I assure you, the coral will not survive.

PLEASE, do not underestimate the quantity and quality of food required by suncorals. ;)
 
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