RTN?!?

[DragonGoby]

Hi guys,

I've got a rather large piece of millipora that until quite recently, was doing pretty OK. The poor thing got knocked over by a huge snail (he's now BANISHED to the sump tank, bwahahahahahaha!!!! ), and thereafter stopped having any open polyps. Shifted it around to see if it will take to a new location, but to no avail. Now, I see some discolouration and loss of tissue from some parts. Is this the dreaded RTN? I've only seen RTN on LPS before, so I'm not sure how it looks like in SPS. In any case, what would be the best solution? I've tried shifting it around to different locations, but it still doesn't pick up growth. Frag it as a last resort?

Thanks!

A desperate reefer ...

Hong Yee

[Phang]

WOw Hong Yee,

This is a very timely topic....

cos I have jus frag my Purple colony due to RTN...

Came home today to find the colony with RTN from tips downwards.... so was forced to frag the whole colony and save what ever I have left.... now 3 pieces of small Live rocks with purple frags all over...

lets see if they recover....

BTW, HongYee, if its RTN, then you have not much time left cos you will most probably lose the whole SPS within half a day.......

Heh..... When you encounter RTN, fragging is never the last resort... it is the only one!!!!...

[Morgan]

Phang

Is this the purple acros I saw?

How is the condition now?

How was the blue..... did it recover?

[Phang]

Hey Morgan, The Purple didn't make it.......

Now one piece left and so let see if it puts out any growth.....

Dun understand why the RTN took place...... the other piece is still fine... and so are the other specimens in my reef......

Anyway, think it all started with my previous batch of purple tips that i managed to rescued from RTN..... it might have triggered this RTN case......

only stange thing is that it was a week ago and between this period, everything looks fine....

[Morgan]

Sorry to hear that the purple did not make it.

[BarraCudaTM]

abit but whats RTN?

[Hon]

RTN stand for Rapid Tissue Necrosis.

This describe syndromes where acropora and other SPS corals rapidly (or not so rapidly) slough tissue from thier skeletons.

There are several patterns of tissue loss. In the first case, the coral rapidly loses tissue from the skeleton. When the coral is subjected to current, many times large clouds of coral tissue will be seen sloughing from the skeleton.

[Phang]

RTN stand for Rapid Tissue Necrosis.

This describe syndromes where acropora and other SPS corals rapidly (or not so rapidly) slough tissue from thier skeletons.

There are several patterns of tissue loss. In the first case, the coral rapidly loses tissue from the skeleton. When the coral is subjected to current, many times large clouds of coral tissue will be seen sloughing from the skeleton.

Jus to add on, RTN happens due to many reasons... of which the major one would be due to stress.... when stressed, SPS esp Acroporas secrete mucous for the protection of their polyps....

This is experience on different levels based on the so called sliming ability of different species....when handled, when placed near other aggressive corals or other SPS in 'sliming mode'.... when such 'slime' is not rid off by excellent circulation, bacteria settles on it and that's normally where RTN starts...

You can actually experience the feel of this mucous when you handle the acros, very thick and slimy ..... they also have a very pungent "aroma to them".......

In Dragongoby case, might be cos he dropped the specimen....

BTW, Dragongoby, hows your milli...???

[BarraCudaTM]

does it apply to SPS only or hardcorals also?

[Phang]

RTN only affects SPS...... cos I never seen or heard LPS RTN, only brown jelly...

the term "rapid" means that the tissue slides of the body at a remarkable rate.... with the SPS losing all of its tissue as quick as hours and at most days........

RTN should not be confused with bleaching..... and many SPS when growing do demonstrates white tips ....

Most corals will slime when handled, jus mother natures way of self protection but it is actually bacteria on unremoved slime with SPS that will start the RTN factor.....

As SPS are predominantly high waterparameter and light demanding species, factors inducing stress in a captive system are pretty common occurances esp when a reefer does not have the means to upkeep the species.....

My last RTN or wave of RTN events have actually to do with a introduced RTN specimen previously which I was trying to save .......

[DragonGoby]

Hmm .. still wondering why that piece started having RTN only after getting knocked off by a snail. I've got 3 Acropora frags and 1 Porites in there are doing well without signs of RTN - is there a chance that it will spread? The SPS are spaced out very well, and the Porites is starting to encrust the surrounding LR as well. Hopefully none of the others get it! Phang, did a frag already, no RTN yet, fingers crossed.

[Phang]

Dragongoby, RTN in a single specimen can and might trigger a onset of RTN cases in other specimens...

Since you have frag the affected colony and managed to slow or stop the RTN process, recommend that you ensure your water quality is maintained..... strong circulation is important at this time....

Check your kh and calcium levels too....

All the Best.... keep us updated.....

BTW, when did you obtained these colony????

[Phang]

RTN only affects SPS...... cos I never seen or heard LPS RTN, only brown jelly...

the term "rapid" means that the tissue slides of the body at a remarkable rate.... with the SPS losing all of its tissue as quick as hours and at most days........

RTN should not be confused with bleaching..... and many SPS when growing do demonstrates white tips ....

Most corals will slime when handled, jus mother natures way of self protection but it is actually bacteria on unremoved slime with SPS that will start the RTN factor.....

As SPS are predominantly high waterparameter and light demanding species, factors inducing stress in a captive system are pretty common occurances esp when a reefer does not have the means to upkeep the species.....

My last RTN or wave of RTN events have actually to do with a introduced RTN specimen previously which I was trying to save .......

Jus to add on .....

It is not the mucous generated by the SPS that results in the RTN.....

cos species are never suicidal ......

It is primary the bacteria infestation of the mucous generated, normally from bad water conditions.... that's why some aquaculture centre tries shipping these SPS under dried methods...by placing shredded wet plastic sheets around the acros with min water... this is too prevent the minimal water which will be bad from long waiting time a lesser chance from affecting the Acros.....

Shipment from these methods have actually resulted with better survival rates compared with standard shipments...

[yazid]

My Gorgonian also looks like having RTN... flesh peeling off.

I start fragging it. Luckily the frag survive.