Brain coral withdrawn

[StarTraveler]

have had an open brain coral in my tank for about 6 months now. It was doing well, expanding, eating every 3 days, good colors, etc. Starting last Mon/Tues. it is completely withdrawn. I see no damage, the tissue seems intact all over, water parameters are doing well, no problems with water that I can tell. All other inhabitants doing fine (xenia, star polyps, brain coral, mushrooms).

i did a 20% water change last night, just inc ase there was something going on I couldn't detect. Any other suggestions ?

[horge]

Hi StarTraveller,

20% is a lot, but then you've been doing this long enough to know how best to care for your tank http://www.thereeftank.com/ubb/smile.gif

Check into territorial aggression from other sessile inverts: are there any others beside those relative wusses (territorially speaking) you listed? It sometimes takes months for other corals to gear up for an attack. Can you list any other such animals in the tank and how they are located relative to your 'open brain'?

Check the coral head at night (with a red/orange-cellophane-covered flashlight) for signs of corallivores like certain snails, crabs, etc. These can be removed with regular diligence. (If the withdrawal took place soon after a feeding, it may be a case of some scavenger stealing food from the coral and learning to like the taste of coral as well.)

Lastly, all corals can go through a phase of tissue contraction. This can last a day up to a week, for some Trachyphyllias and Lobophyllias. It seems connected to either growth spurts or (if the colony is sexually mature) a wrongheaded/abortive attempt to gear up for spawning. No biggie. I would have stated this first, but I presumed you wouldn't have brought this up here if it wasn't a more severe case http://www.thereeftank.com/ubb/smile.gif

HTH, and give more details!

[This message has been edited by horge (edited 09-22-2000).]

[StarTraveler]

Thanks for the reply. The tank is still relatively new, less than 1 year. Closest is the bubble, but it is only about 3" across fully expanded and about 4" from the brain. Xenia is also about 4", down current. Nothing in the tank is really aggressive except for the bubble at close range.

1 peppermint, assorted blue legs and left handed hermits, 5-6 astreas, 3 bumblebee snails, 2 unknown crabs, very pretty, about 1/2" across the carapice but with large "nets" for front claws, holds them in the current to feed. I usually feed the brain late at night and his feeders are up and out. I have never (including now) seen any crabs of ay type mess with him.

20% was a bit, but I did it as a "just in case" there was something in the water I couldn't test for. As of tonight parameters still OK, will wait and see for now.

Thanks again, Horge

[This message has been edited by StarTraveler (edited 09-22-2000).]

[horge]

Bubble Coral (Plerogyra sinuosa) are among the more aggessive corals. If you suspect any interaction, it wouldn't hurt to put more distance, or a barrier even, between the two.

4" is peanuts compared to how far a healthy Bubble's sweeper tentacles can reach out, and the Bubble colony's small size does not detract from its individual polyps' potential to harm other corals http://www.thereeftank.com/ubb/eek.gif

It may not be the Bubble, but it'd certainly be on my list of suspects http://www.thereeftank.com/ubb/smile.gif

Happy hunting.

[StarTraveler]

Already did it. However, the brain started to open quite a bit on Sat. evening, and again Sun. Not fully open, but a lot better.

I will wait and see what happens, I will do another small water change tonight, and go from there.

Thanks.