coral branch appears to be dissolving

[shadowfish]

Hi,

I have a 40 gallon reef only tank, with 175 watt MH lights, one piece of Povona (leaf coral) frag, two Tridacna clams, several mushrooms, xenia (spread out), small star coral, one candy cane coral and a branching hammer coral (about 6 branches).

My question is that over the last 6-8 months, the branches of the hammer coral appear to be dissolving. All pH, Nitrates, Nitrites, Calcium, Iodine, Salinity, Temp,… appear to be normal (maintain most through additives). The clams (I have had them for over two years) and the Povona (1.5 years) are growing (I can see new growth) and doing well. The Hammer has lost some of it's color, but still appears to be doing well. It is even sprouting new “tentacles”.

I am concerned because I think that one of the branches will be falling off within the next several months.

I thought that pH might be a problem, but after testing regularly, it appears to remain constant. Any thoughts, ideas or help would be greatly appreciated?

Thanks

Marty

[reefrunner69]

Can we grt a pic of the coral?

What is the ALK? What is the temp?

[shadowfish]

Thanks for the response...

Looking back on my logs I found that:
Temp is pretty consistent... winter months - 74 degrees summer 78 degrees.

Alk is between 3.5 and 4
Calcium is around 450 (does fluctuate between 400 and 500)
Iodine is usually low - I regularly add several drops of Iodine
Salinity is high 1.025 +/- .001 - I like it high, corals look much better a little on the high side.
I use C-balance regularly

I hope the picture helps. I took it before the lights came on (easier to see branch). One other point is that the hermit crab shells also appear to be dissolving, but the clams and the Pavona look great! I thought that if it was a chemical imbalance it would effect all pieces.

Thanks

Marty

[shadowfish]

Sorry - operator error...

I included the wrong picture then an extra one...

Here is the picture of the dissolving shell...

Marty

Looks like you have a type of boring algae in the scleractinia known as Ostreobium. Not sure what you can do about it aside from fraggging and an iodoine dip. I have seen it happen before and the algae colony will often crash on it's own but not always. Once the coral grows beyond the damaged areas, it can be cut away fairly easily.

Cheers
Steve

[shadowfish]

Thanks Steve,

Is there a visible way I can tell that I have this (so I can tell if it is gone or not)? Can I expect it to attach other corals or clams in the tank? Should I quarantine the healthy ones?

Tried to find some info on Web, but did not find much. One indicated that it is believed to attack only unhealthy pieces. Do you believe this is what is attacking the shells also? Any suggestions on where I can find more info on this algae ?

Thanks

Marty

It is not so much that it attacks unhealthy corals but rather the dead parts of the scleractinia. In basically bores into the CaCO3 skelaton and consumes it. From what I have been able to glean from very few articles, is that they are very low light zooxanthellae type algaes that will not do well in direct full light. I would ensure the affected area is upturned and gets good water flow.

As far as being able to tell when it's gone.... I would say the a color change in the scleractinia to a duller less greenish appearance would be an indication but that's more a guess than anything.

Where the snail shells like that in short time or over a few months? Could be simple CaCO3 decay common when the animal is no longer present.

What I would actually suggest is sending your pic to Eric Borneman and see if he may be able to help EricHugo@aol.com. Unless someone else has anything to add?

Cheers
Steve