Yes Kunhardt, that you are right - it is not a Tubastrea but a Dendrophyllia sp. Not that the game changes, it's just the players... Technically it is not a suncoral, but to make it easier let us refer to it that way...
The bad news here however is that Dendrophyllia is much much more difficult to keep than Tubastrea. Black Suncoral is also a Dendrophyllia sp. and those who have kept it will agree.
The problem with this specific suncoral you have, is that you cannot judge the health by looking at tissue loss. It does not stay orange though, but it also does not have that white skeleton that other suncorals have.
So, I must admit yours is very very far from happy - but not dead. Many of the heads are very retracted but the mouths are still there, so there might be hope.
I have read about the advise of taking it out into a container etc. but from my experience please do not do this. If you cannot handle the coral without touching any tissue, do not touch it at all. They are very sensitive to touch. If you touch a healthy Dendro then you leave a fingerprint on it and some tissue will in fact be left on your finger like dust. This can cause further damage and it takes long to regrow the lost tissue.
So, in my opinion please revert from touching it - tubastrea is different as it has a softer tisseu, but still they generally do not like being handled much.
So, unless you can handle it without touching the tissue then it is fine.
Also, where suncorals are located in the wild, they are not tidal corals, so they do not fair well being exposed to air all the time. Try and keep them under water as much as you can.
So, I would suggest going with the bottle feed method on this one. Place him on the substrate (dont worry about the light at all) and if it has polyps sticking in the sand, use a pvc pipe to lift it out like LFS does keeping LPS corals in their tanks.
Then cut out the bottom piece of a 2l coke bottle to fit over it. The trick is to try and fit the bottle over it, without touching the suncoral as again, they do not like to be handled. Then you squirt food into the bottle and close the cap. Leave it for about 5-10mins, then open the cap just a tad. The flow will "move" the food around a bit in the bottle, then you cap the bottle again. After another 15minutes you can take the bottle off...
Do not leave the bottle overnight for example, as you have 2 litres of water with huge amounts of food in it, so it will build up ammonia etc quite fast.
You cannot save nor survive this coral by feeding it twice a week. You will have to feed this way at least once a day, and if time allows, twice or as much as you can.
Leave it in that same spot, and keep on feeding, just dont give up.
What to feed? A suncoral in this state is not able to capture food with it's tentacles - it is far too weak. It will not even open up it's tentacles, as it is too weak. This feeding with fitler feeding food is crucial now. It cannot capture brine or mysis, so dont even waste your time with it, unless you much it into a soup. Rather get some Brigtwells Amin-Omega, reef snow, phyto plankton and zoo plankton and mix it all up into a milk. Dont be shy.
You will see the mouths swelling up nicely once the food is in the container. What the coral is doing then is basically "breathing" in the food. This will SLOWLY help it gain energy, and then after a few weeks you will notice some yellow dots as they tentacles start coming out. Then a few weeks later it will show some tentacles. Then you can start feeding live brine shrimp nauplii and cyclop-eeze.
Only once the coral is able to capture prey in normal flow conditions, and opening up really well, would I suggest moving it to another spot. Remember again to handle with utmost care.
This is not a quick fix coral - I promise you, I am still having problems with a suncoral that is over 1 1/2 years old, so have patience...
Good luck and if you have questions, please feel free to ask...
