STN

[ss88]

In general all other coral colonies are healthy.

Recently moved this system. One of the Acropora corals has started to rtn. Not sure the exact start date, most likely 4-5 days.

ppears that some type of pest might have initiated the RTN.

Should I frag the colony to save it or wait another day or so to evaluate.

Second picture shows the unidentifiable inhabitant inside the dead skeleton.

 

[ss88]

Alkalinity has fluxuated from 7.8 to 7.35 over the course of a week due to demand changes. Recently changed from soda ash to sodium hydroxide resulting in a pH +0.2 increase average 8.2/8.4 Needless to say, alkalinity demand doubled clearly a sign of increased growth. Daily pH cycle is less then .05 due to dual tanks running reverse lighting cycle.

 

[Dburr1014]

Alkalinity has fluxuated from 7.8 to 7.35 over the course of a week due to demand changes. Recently changed from soda ash to sodium hydroxide resulting in a pH +0.2 increase average 8.2/8.4 Needless to say, alkalinity demand doubled clearly a sign of increased growth. Daily pH cycle is less then .05 due to dual tanks running reverse lighting cycle.

I would definitely snap a couple frags off, dip them, and remount.
That small alkalinity fluctuation didn't do this or the ph.
Most likely the move, can you tell me more about that?
I can't see any pest, can you point it out?

 

[ss88]

Move occurred around 1 month ago.
Everything moved rather carefully inside large coolers. Nothing else has deteriorated, knock on wood. The only ptgeer thing i can think is lack of flow and light shock. This particular guy was in high lighting and high flow. He is now in lower level flow and a corner of the tank with lower light. Particularly the area of the coral colony that has stn first is sheltered the most resulting in less flow and light.

 

[ss88]

Picture

 

[BranchingHammer]

Perhaps it was a result of the Monti stinging the colony repeatedly? And those are micro brittle stars on the branches in the last photo. They are harmless detritus eaters.

 

[guylaga]

Looks like a brittle star has moved in where the flesh has died off. Doubt they would be the source of the RTN.

 

[Dburr1014]

Picture

Brittle star, harmless.
Well, I would snap off a couple frags and move it into higher flow. It needs to shed off dieing flesh. Has it advanced more?
It may not make it. Cut frags with only living flesh and dip them.

 

[ss88]

Recommended dip and procedure?
Was thinking ciprofloxacin and Coral rx together.
should i frag the whole colony into 2”x2”sections? Its about 8x6 total. Or frag into one large segment and 3/4 smaller frags?
some of the colony still has decent pe.

 

[Dburr1014]

Recommended dip and procedure?
Was thinking ciprofloxacin and Coral rx together.
should i frag the whole colony into 2”x2”sections? Its about 8x6 total. Or frag into one large segment and 3/4 smaller frags?
some of the colony still has decent pe.

Coral rx. For sure at least one small frag.
You could break off the bad section and get it out of the tank. It may or may not survive. 50/50 shot. That's a pretty big colony. I guess if it were me, I would definitely break off one or two small pieces and try to get the bad section out if it was in one big section that I could remove easily.

 

[ss88]

This colony is attached to a 2’x2’ monti. No possible way to remove the infected section without removing the rest of the colony.

What about an iodine dip?

 

[ss88]

Figured I would give an update and provide a cautionary note.

I now understand RTN and STN a lot better. At least I think i do. I’d be willing to wager that the bacteria(s) or protozoan(s) that causes RTN/STN are always in our systems. These bacteria are likely normally benign. Its only when the colony is stressed from other factors do these pathogens have the ability to enter the host. I have also noticed that the rate of tissue loss appears to increase during a photo period.

This particular coral colony initially improved, had great polyp extension and color improvements. The frags that I extracted are still alive and well as of today.

The cautionary story.

Hurricane Ian, definitely created an issue in the system. I was unable to clean aquarium normally for a week, as a result, I had a massive algae bloom. I decided to use filter floss to wipe down the walls of the aquarium and apply filter floss to the power heads to clear debris in the water faster. Initially not an issue for the first week, when the second week arrived I noticed that some stringy algae was forming around some of the SPS tips. Very alarming. Removed a few pcs of algae from the tips of the sps and determined the cause. The filter floss became entangled in some of the sps coral colonies. This particular SPS coral colony was especially susceptible because of its tight branch skeleton structure. While I was able to remove 90% of the filter floss fibers from this particular colony, it was still adversely affected and stressed by the nuisance algae formation. Fast forward to 3 days ago, the section of the coral colony I was unable to extract the filter floss from started to have complete polyp retraction. As such, it started to RTN yesterday. I did proceed forward with the same protocol, hopefully some of these new frags survive.

In summary, the sps colony was not 100% recovered from the first stress event. Had two subsequent stressful events alk swing from hurricane Ian and filter floss entanglement as a result an RTN event occurred yesterday. I wont be using filter floss to clean the aquarium again.


An important but perhaps unrelated note, yesterday I dosed Microbacter 7. While I don’t have years of experience using this product, the short timeframe I have used it appears to have produced positive results concerning nuisance algae control and is not posed a problem in the past. I am however weary that the bacteria in this product may have contributed to the RTN event as the coral was already stressed.

Stressed coral with weekend immune system + massive scavenging bacteria addition = RTN? Will definitely avoid using bacteria products and will caution others on using any type of bacteria adding products or potential causing a bacterial bloom if an sps coral colony is stressed. It might just send it into RTN.

 

[Naturalreef]

Another interesting note regarding RTN. I always notice polyp retraction before a coral RTN’s. I have a frag that still has its polyps retracted from overexposure to UV led’s. I’m treating my tank with Triton RTN-X to hopefully protect this frag from possible RTN.

My other frag also had no polyp extension the day before and the next morning was RTN’ing. Also possibly a factor….don’t dose aminos after a stress event for a few days, possibly a week. I feel it either fuels the bad bacteria or it stresses the already stressed coral.

Coral definitely have a reserve built in. If they are fed properly with parameters in check, they usually have 1-2 minor-mid events they will recover from before bailing In my experience.

just some thoughts, not facts:)

 

[sculpin01]

I would consider cipro for potential Arcobacter in this case.